Merge branch 'master' of https://github.com/chkr1011/MQTTnet

Fix infinite loop when the client closes the connection

.gitignore

@@ -291,3 +291,5 @@ __pycache__/
 Build/nuget.exe
 *.js
 *.map
+
+/Tests/MQTTnet.TestApp.NetCore/RetainedMessages.json

Build/MQTTnet.AspNetCore.nuspec

@@ -2,7 +2,7 @@
 <package >
   <metadata>
     <id>MQTTnet.AspNetCore</id>
-    <version>2.5.3</version>
+    <version>2.7.0</version>
     <authors>Christian Kratky</authors>
     <owners>Christian Kratky</owners>
     <licenseUrl>https://github.com/chkr1011/MQTTnet/blob/master/LICENSE</licenseUrl>
@@ -10,13 +10,13 @@
     <iconUrl>https://raw.githubusercontent.com/chkr1011/MQTTnet/master/Images/Logo_128x128.png</iconUrl>
     <requireLicenseAcceptance>false</requireLicenseAcceptance>
     <description>This is a support library to integrate MQTTnet into AspNetCore.</description>
-    <releaseNotes>* Updated to MQTTnet 2.5.3.
+    <releaseNotes>* Updated to MQTTnet 2.7.0.
     </releaseNotes>
-    <copyright>Copyright Christian Kratky 2016-2017</copyright>
+    <copyright>Copyright Christian Kratky 2016-2018</copyright>
     <tags>MQTT Message Queue Telemetry Transport MQTTClient MQTTServer Server MQTTBroker Broker NETStandard IoT InternetOfThings Messaging Hardware Arduino Sensor Actuator M2M ESP Smart Home Cities Automation Xamarin</tags> 
     <dependencies>
       <group targetFramework="netstandard2.0">
-        <dependency id="MQTTnet" version="2.5.3-rc1" />
+        <dependency id="MQTTnet" version="2.7.0" />
       </group>
     </dependencies>
   </metadata>

Build/MQTTnet.Extensions.Rpc.nuspec

@@ -0,0 +1,47 @@
+<?xml version="1.0"?>
+<package >
+  <metadata>
+    <id>MQTTnet.Extensions.Rpc</id>
+    <version>2.6.0</version>
+    <authors>Christian Kratky</authors>
+    <owners>Christian Kratky</owners>
+    <licenseUrl>https://github.com/chkr1011/MQTTnet/blob/master/LICENSE</licenseUrl>
+    <projectUrl>https://github.com/chkr1011/MQTTnet</projectUrl>
+    <iconUrl>https://raw.githubusercontent.com/chkr1011/MQTTnet/master/Images/Logo_128x128.png</iconUrl>
+    <requireLicenseAcceptance>false</requireLicenseAcceptance>
+    <description>This is a extension library which allows executing synchronous device calls including a response using MQTTnet.</description>
+    <releaseNotes>* Initial version.
+    </releaseNotes>
+    <copyright>Copyright Christian Kratky 2016-2017</copyright>
+    <tags>MQTT Message Queue Telemetry Transport MQTTClient MQTTServer Server MQTTBroker Broker NETStandard IoT InternetOfThings Messaging Hardware Arduino Sensor Actuator M2M ESP Smart Home Cities Automation Xamarin</tags> 
+    <dependencies>
+      <group targetFramework="netstandard2.0">
+        <dependency id="MQTTnet" version="2.6.0-rc1" />
+      </group>
+      <group targetFramework="netstandard1.3">
+        <dependency id="MQTTnet" version="2.6.0-rc1" />  
+      </group>
+
+      <group targetFramework="netstandard2.0">
+        <dependency id="MQTTnet" version="2.6.0-rc1" />
+      </group>
+      
+      <group targetFramework="uap10.0">
+        <dependency id="MQTTnet" version="2.6.0-rc1" />
+      </group>
+        
+      <group targetFramework="net452">
+        <dependency id="MQTTnet" version="2.6.0-rc1" />
+      </group>
+
+      <group targetFramework="net461">
+        <dependency id="MQTTnet" version="2.6.0-rc1" />
+      </group>
+    </dependencies>
+  </metadata>
+
+  <files>
+    <!-- .NET Standard 2.0 -->
+    <file src="..\Frameworks\MQTTnet.AspNetCore\bin\Release\netstandard2.0\MQTTnet.AspNetCore.*" target="lib\netstandard2.0\"/>
+  </files>
+</package>

Build/MQTTnet.nuspec

@@ -2,7 +2,7 @@
 <package >
   <metadata>
     <id>MQTTnet</id>
-    <version>2.5.3</version>
+    <version>2.7.0</version>
     <authors>Christian Kratky</authors>
     <owners>Christian Kratky</owners>
     <licenseUrl>https://github.com/chkr1011/MQTTnet/blob/master/LICENSE</licenseUrl>
@@ -10,11 +10,18 @@
     <iconUrl>https://raw.githubusercontent.com/chkr1011/MQTTnet/master/Images/Logo_128x128.png</iconUrl>
     <requireLicenseAcceptance>false</requireLicenseAcceptance>
     <description>MQTTnet is a high performance .NET library for MQTT based communication. It provides a MQTT client and a MQTT server (broker).</description>
-    <releaseNotes>* [Core] Removed all dependencies to other libraries (BREAKING CHANGE!).
+    <releaseNotes>* [Core] Fixed some still thread blocking parts in the code (thanks to @kpreisser).
-* [Core] Updated SDK libraries.
+* [Core] Updated 3rd-Party packages.
-* [Client] Fixed broken support for WebSocketSecure connections (Thanks to @StAI).
+* [Core] Fixed wrong packet identifier calculation (thanks to @benpittoors).
+* [Core] Fixed an issue when reading the body of a package from a disconnected sender (thanks to @kpreisser).
+* [Core] Fixed wrong parsing of the body length (thanks to @kpreisser).
+* [Client] The client interfaces are now implementing _IDisposable_.
+* [Client] The disconnected event now contains the exception which was thrown and causing the disconnect.
+* [Server] Fixed an issue which lets the server block 1 second after accepting a new connection (thanks to @kpreisser).
+* [Server] The server now allows managing client subscriptions.
+* [Server] Added events for topic subscriptions.
     </releaseNotes>
-    <copyright>Copyright Christian Kratky 2016-2017</copyright>
+    <copyright>Copyright Christian Kratky 2016-2018</copyright>
     <tags>MQTT Message Queue Telemetry Transport MQTTClient MQTTServer Server MQTTBroker Broker NETStandard IoT InternetOfThings Messaging Hardware Arduino Sensor Actuator M2M ESP Smart Home Cities Automation Xamarin</tags> 
     <dependencies>
 
@@ -46,23 +53,18 @@
   </metadata>
 
   <files>
+    
     <!-- .NET Standard 1.3 -->
-    <file src="..\Frameworks\MQTTnet.Netstandard\bin\Release\netstandard1.3\MQTTnet.Core.*" target="lib\netstandard1.3\"/>
     <file src="..\Frameworks\MQTTnet.Netstandard\bin\Release\netstandard1.3\MQTTnet.*" target="lib\netstandard1.3\"/>
     
     <!-- .NET Standard 2.0 -->
-    <file src="..\Frameworks\MQTTnet.Netstandard\bin\Release\netstandard2.0\MQTTnet.Core.*" target="lib\netstandard2.0\"/>
     <file src="..\Frameworks\MQTTnet.Netstandard\bin\Release\netstandard2.0\MQTTnet.*" target="lib\netstandard2.0\"/>
 
     <!-- Universal Windows -->
-    <file src="..\Frameworks\MQTTnet.Netstandard\bin\Release\uap10.0\MQTTnet.Core.*" target="lib\uap10.0\"/>
     <file src="..\Frameworks\MQTTnet.Netstandard\bin\Release\uap10.0\MQTTnet.*" target="lib\uap10.0\"/>
 
     <!-- .NET Framework -->
-    <file src="..\Frameworks\MQTTnet.Netstandard\bin\Release\net452\MQTTnet.Core.*" target="lib\net452\"/>
     <file src="..\Frameworks\MQTTnet.Netstandard\bin\Release\net452\MQTTnet.*" target="lib\net452\"/>
-
-    <file src="..\Frameworks\MQTTnet.Netstandard\bin\Release\net461\MQTTnet.Core.*" target="lib\net461\"/>
     <file src="..\Frameworks\MQTTnet.Netstandard\bin\Release\net461\MQTTnet.*" target="lib\net461\"/>
     
   </files>

Build/build.ps1

@@ -8,16 +8,26 @@ $path = &$vswhere -latest -products * -requires Microsoft.Component.MSBuild -pro
 if ($path) {
     $msbuild = join-path $path 'MSBuild\15.0\Bin\MSBuild.exe'
 
+	# Build the core library
     &$msbuild ..\Frameworks\MQTTnet.Netstandard\MQTTnet.Netstandard.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="net452" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m
     &$msbuild ..\Frameworks\MQTTnet.Netstandard\MQTTnet.Netstandard.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="net461" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m
     &$msbuild ..\Frameworks\MQTTnet.Netstandard\MQTTnet.Netstandard.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="netstandard1.3" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m
     &$msbuild ..\Frameworks\MQTTnet.Netstandard\MQTTnet.Netstandard.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="netstandard2.0" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m
     &$msbuild ..\Frameworks\MQTTnet.Netstandard\MQTTnet.Netstandard.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="uap10.0" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m
     
+	# Build the ASP.NET Core 2.0 extension
 	&$msbuild ..\Frameworks\MQTTnet.AspNetCore\MQTTnet.AspNetCore.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="netstandard2.0" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m
 
+	# Build the RPC extension
+	&$msbuild ..\Extensions\MQTTnet.Extensions.Rpc\MQTTnet.Extensions.Rpc.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="net452" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m
+    &$msbuild ..\Extensions\MQTTnet.Extensions.Rpc\MQTTnet.Extensions.Rpc.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="net461" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m
+    &$msbuild ..\Extensions\MQTTnet.Extensions.Rpc\MQTTnet.Extensions.Rpc.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="netstandard1.3" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m
+    &$msbuild ..\Extensions\MQTTnet.Extensions.Rpc\MQTTnet.Extensions.Rpc.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="netstandard2.0" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m
+    &$msbuild ..\Extensions\MQTTnet.Extensions.Rpc\MQTTnet.Extensions.Rpc.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="uap10.0" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m
+
     Remove-Item .\NuGet -Force -Recurse
     New-Item -ItemType Directory -Force -Path .\NuGet
     .\NuGet.exe pack MQTTnet.nuspec -Verbosity detailed -Symbols -OutputDir "NuGet" -Version $nugetVersion
     .\NuGet.exe pack MQTTnet.AspNetCore.nuspec -Verbosity detailed -Symbols -OutputDir "NuGet" -Version $nugetVersion
+	.\NuGet.exe pack MQTTnet.Extensions.Rpc.nuspec -Verbosity detailed -Symbols -OutputDir "NuGet" -Version $nugetVersion
 }

Documents/Import_CodeSigningKey.md

@@ -0,0 +1,6 @@
+# Import codeSigningKey.pfx
+In order to import the key for code signing on a new developer machine use the following command within the VS developer command line:
+
+> sn –i codeSigningKey.pfx VS_KEY_EFCA4C5B6DFD4B4F
+
+The container name may be different.

Extensions/MQTTnet.Extensions.Rpc/MQTTnet.Extensions.Rpc.csproj

@@ -0,0 +1,30 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFrameworks>netstandard1.3;netstandard2.0;net452;net461;uap10.0</TargetFrameworks>
+    <AssemblyVersion>0.0.0.0</AssemblyVersion>
+    <FileVersion>0.0.0.0</FileVersion>
+    <Product />
+    <Company />
+    <Authors />
+    <PackageId />
+    <Version>0.0.0.0</Version>
+  </PropertyGroup>
+
+  <PropertyGroup Condition="'$(TargetFramework)' == 'uap10.0'">
+    <CopyLocalLockFileAssemblies>false</CopyLocalLockFileAssemblies>
+    <NugetTargetMoniker>UAP,Version=v10.0</NugetTargetMoniker>
+    <TargetPlatformIdentifier>UAP</TargetPlatformIdentifier>
+    <TargetPlatformVersion>10.0.16299.0</TargetPlatformVersion>
+    <TargetPlatformMinVersion>10.0.10240.0</TargetPlatformMinVersion>
+    <TargetFrameworkIdentifier>.NETCore</TargetFrameworkIdentifier>
+    <TargetFrameworkVersion>v5.0</TargetFrameworkVersion>
+    <DefineConstants>$(DefineConstants);WINDOWS_UWP</DefineConstants>
+    <LanguageTargets>$(MSBuildExtensionsPath)\Microsoft\WindowsXaml\v$(VisualStudioVersion)\Microsoft.Windows.UI.Xaml.CSharp.targets</LanguageTargets>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\Frameworks\MQTTnet.Netstandard\MQTTnet.NetStandard.csproj" />
+  </ItemGroup>
+
+</Project>

Extensions/MQTTnet.Extensions.Rpc/MqttRpcClient.cs

@@ -0,0 +1,101 @@
+using System;
+using System.Collections.Concurrent;
+using System.Threading.Tasks;
+using MQTTnet.Client;
+using MQTTnet.Internal;
+using MQTTnet.Protocol;
+
+namespace MQTTnet.Extensions.Rpc
+{
+    public sealed class MqttRpcClient : IDisposable
+    {
+        private const string ResponseTopic = "$MQTTnet.RPC/+/+/response";
+        private readonly ConcurrentDictionary<string, TaskCompletionSource<byte[]>> _waitingCalls = new ConcurrentDictionary<string, TaskCompletionSource<byte[]>>();
+        private readonly IMqttClient _mqttClient;
+        private bool _isEnabled;
+
+        public MqttRpcClient(IMqttClient mqttClient)
+        {
+            _mqttClient = mqttClient ?? throw new ArgumentNullException(nameof(mqttClient));
+
+            _mqttClient.ApplicationMessageReceived += OnApplicationMessageReceived;
+        }
+
+        public async Task EnableAsync()
+        {
+            await _mqttClient.SubscribeAsync(new TopicFilterBuilder().WithTopic(ResponseTopic).WithAtLeastOnceQoS().Build());
+            _isEnabled = true;
+        }
+
+        public async Task DisableAsync()
+        {
+            await _mqttClient.UnsubscribeAsync(ResponseTopic);
+            _isEnabled = false;
+        }
+
+        public async Task<byte[]> ExecuteAsync(TimeSpan timeout, string methodName, byte[] payload, MqttQualityOfServiceLevel qualityOfServiceLevel)
+        {
+            if (methodName == null) throw new ArgumentNullException(nameof(methodName));
+
+            if (methodName.Contains("/") || methodName.Contains("+") || methodName.Contains("#"))
+            {
+                throw new ArgumentException("The method name cannot contain /, + or #.");
+            }
+
+            if (!_isEnabled)
+            {
+                throw new InvalidOperationException("The RPC client is not enabled.");
+            }
+
+            var requestTopic = $"$MQTTnet.RPC/{Guid.NewGuid():N}/{methodName}";
+            var responseTopic = requestTopic + "/response";
+
+            var requestMessage = new MqttApplicationMessageBuilder()
+                .WithTopic(requestTopic)
+                .WithPayload(payload)
+                .WithQualityOfServiceLevel(qualityOfServiceLevel)
+                .Build();
+
+            try
+            {
+                var tcs = new TaskCompletionSource<byte[]>();
+                if (!_waitingCalls.TryAdd(responseTopic, tcs))
+                {
+                    throw new InvalidOperationException();
+                }
+
+                await _mqttClient.PublishAsync(requestMessage);
+                return await tcs.Task.TimeoutAfter(timeout);
+            }
+            finally
+            {
+                _waitingCalls.TryRemove(responseTopic, out _);
+            }
+        }
+
+        private void OnApplicationMessageReceived(object sender, MqttApplicationMessageReceivedEventArgs eventArgs)
+        {
+            if (!_waitingCalls.TryRemove(eventArgs.ApplicationMessage.Topic, out TaskCompletionSource<byte[]> tcs))
+            {
+                return;
+            }
+
+            if (tcs.Task.IsCompleted || tcs.Task.IsCanceled)
+            {
+                return;
+            }
+
+            tcs.TrySetResult(eventArgs.ApplicationMessage.Payload);
+        }
+
+        public void Dispose()
+        {
+            foreach (var tcs in _waitingCalls)
+            {
+                tcs.Value.SetCanceled();
+            }
+
+            _waitingCalls.Clear();
+        }
+    }
+}

Extensions/MQTTnet.Extensions.Rpc/SampleCCode.c

@@ -0,0 +1 @@
+

Frameworks/MQTTnet.AspnetCore/ApplicationBuilderExtensions.cs

@@ -1,8 +1,8 @@
 using System;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.Extensions.DependencyInjection;
-using MQTTnet.Core.Server;
 using System.Linq;
+using MQTTnet.Server;
 
 namespace MQTTnet.AspNetCore
 {

Frameworks/MQTTnet.AspnetCore/MQTTnet.AspnetCore.csproj

@@ -2,14 +2,23 @@
 
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>
-    <AssemblyVersion>2.5.2.0</AssemblyVersion>
+    <AssemblyVersion>0.0.0.0</AssemblyVersion>
-    <FileVersion>2.5.2.0</FileVersion>
+    <FileVersion>0.0.0.0</FileVersion>
+    <Version>0.0.0.0</Version>
+    <Product />
+    <Company />
+    <Authors />
+    <PackageId />
+  </PropertyGroup>
+
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|AnyCPU'">
+    <DefineConstants>RELEASE;NETSTANDARD2_0</DefineConstants>
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.AspNetCore.Http.Abstractions" Version="2.0.0" />
+    <PackageReference Include="Microsoft.AspNetCore.Http.Abstractions" Version="2.0.1" />
-    <PackageReference Include="Microsoft.AspNetCore.WebSockets" Version="2.0.0" />
+    <PackageReference Include="Microsoft.AspNetCore.WebSockets" Version="2.0.1" />
-    <PackageReference Include="Microsoft.Extensions.Hosting.Abstractions" Version="2.0.0" />
+    <PackageReference Include="Microsoft.Extensions.Hosting.Abstractions" Version="2.0.1" />
   </ItemGroup>
 
   <ItemGroup>

Frameworks/MQTTnet.AspnetCore/MqttHostedServer.cs

@@ -3,17 +3,17 @@ using System.Collections.Generic;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.Extensions.Hosting;
-using MQTTnet.Core.Adapter;
+using MQTTnet.Adapter;
-using MQTTnet.Core.Diagnostics;
+using MQTTnet.Diagnostics;
-using MQTTnet.Core.Server;
+using MQTTnet.Server;
 
 namespace MQTTnet.AspNetCore
 {
     public class MqttHostedServer : MqttServer, IHostedService
     {
-        private readonly MqttServerOptions _options;
+        private readonly IMqttServerOptions _options;
 
-        public MqttHostedServer(MqttServerOptions options, IEnumerable<IMqttServerAdapter> adapters, IMqttNetLogger logger) : base(adapters, logger)
+        public MqttHostedServer(IMqttServerOptions options, IEnumerable<IMqttServerAdapter> adapters, IMqttNetLogger logger) : base(adapters, logger)
         {
             _options = options ?? throw new ArgumentNullException(nameof(options));
         }

Frameworks/MQTTnet.AspnetCore/MqttWebSocketServerAdapter.cs

@@ -1,18 +1,18 @@
 using System;
 using System.Net.WebSockets;
 using System.Threading.Tasks;
-using MQTTnet.Core.Adapter;
+using MQTTnet.Adapter;
-using MQTTnet.Core.Diagnostics;
+using MQTTnet.Diagnostics;
-using MQTTnet.Core.Serializer;
+using MQTTnet.Serializer;
-using MQTTnet.Core.Server;
+using MQTTnet.Server;
 
 namespace MQTTnet.AspNetCore
 {
-    public class MqttWebSocketServerAdapter : IMqttServerAdapter, IDisposable
+    public sealed class MqttWebSocketServerAdapter : IMqttServerAdapter, IDisposable
     {
         public event EventHandler<MqttServerAdapterClientAcceptedEventArgs> ClientAccepted;
 
-        public Task StartAsync(MqttServerOptions options)
+        public Task StartAsync(IMqttServerOptions options)
         {
             return Task.CompletedTask;
         }

Frameworks/MQTTnet.AspnetCore/MqttWebSocketServerChannel.cs

@@ -3,7 +3,7 @@ using System.IO;
 using System.Net.WebSockets;
 using System.Threading;
 using System.Threading.Tasks;
-using MQTTnet.Core.Channel;
+using MQTTnet.Channel;
 using MQTTnet.Implementations;
 
 namespace MQTTnet.AspNetCore

Frameworks/MQTTnet.AspnetCore/ServiceCollectionExtensions.cs

@@ -1,15 +1,15 @@
 using System;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;
-using MQTTnet.Core.Adapter;
+using MQTTnet.Adapter;
-using MQTTnet.Core.Diagnostics;
+using MQTTnet.Diagnostics;
-using MQTTnet.Core.Server;
+using MQTTnet.Server;
 
 namespace MQTTnet.AspNetCore
 {
     public static class ServiceCollectionExtensions
     {
-        public static IServiceCollection AddHostedMqttServer(this IServiceCollection services, MqttServerOptions options)
+        public static IServiceCollection AddHostedMqttServer(this IServiceCollection services, IMqttServerOptions options)
         {
             if (options == null) throw new ArgumentNullException(nameof(options));
 

Frameworks/MQTTnet.NetStandard/Adapter/IMqttChannelAdapter.cs

@@ -2,10 +2,10 @@
 using System.Collections.Generic;
 using System.Threading;
 using System.Threading.Tasks;
-using MQTTnet.Core.Packets;
+using MQTTnet.Packets;
-using MQTTnet.Core.Serializer;
+using MQTTnet.Serializer;
 
-namespace MQTTnet.Core.Adapter
+namespace MQTTnet.Adapter
 {
     public interface IMqttChannelAdapter
     {

Frameworks/MQTTnet.NetStandard/Adapter/IMqttServerAdapter.cs

@@ -1,14 +1,14 @@
 using System;
 using System.Threading.Tasks;
-using MQTTnet.Core.Server;
+using MQTTnet.Server;
 
-namespace MQTTnet.Core.Adapter
+namespace MQTTnet.Adapter
 {
     public interface IMqttServerAdapter
     {
         event EventHandler<MqttServerAdapterClientAcceptedEventArgs> ClientAccepted;
 
-        Task StartAsync(MqttServerOptions options);
+        Task StartAsync(IMqttServerOptions options);
         Task StopAsync();
     }
 }

Frameworks/MQTTnet.NetStandard/Adapter/MqttChannelAdapter.cs

@@ -1,21 +1,23 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Net.Sockets;
 using System.Runtime.InteropServices;
 using System.Threading;
 using System.Threading.Tasks;
-using MQTTnet.Core.Channel;
+using MQTTnet.Channel;
-using MQTTnet.Core.Diagnostics;
+using MQTTnet.Diagnostics;
-using MQTTnet.Core.Exceptions;
+using MQTTnet.Exceptions;
-using MQTTnet.Core.Internal;
+using MQTTnet.Internal;
-using MQTTnet.Core.Packets;
+using MQTTnet.Packets;
-using MQTTnet.Core.Serializer;
+using MQTTnet.Serializer;
 
-namespace MQTTnet.Core.Adapter
+namespace MQTTnet.Adapter
 {
     public class MqttChannelAdapter : IMqttChannelAdapter
     {
         private const uint ErrorOperationAborted = 0x800703E3;
+        private const int ReadBufferSize = 4096;  // TODO: Move buffer size to config
 
         private readonly SemaphoreSlim _semaphore = new SemaphoreSlim(1, 1);
         private readonly IMqttNetLogger _logger;
@@ -30,23 +32,23 @@ namespace MQTTnet.Core.Adapter
 
         public IMqttPacketSerializer PacketSerializer { get; }
 
-        public async Task ConnectAsync(TimeSpan timeout)
+        public Task ConnectAsync(TimeSpan timeout)
         {
-            _logger.Info<MqttChannelAdapter>("Connecting [Timeout={0}]", timeout);
+            _logger.Trace<MqttChannelAdapter>("Connecting [Timeout={0}]", timeout);
 
-            await ExecuteAndWrapExceptionAsync(() => _channel.ConnectAsync().TimeoutAfter(timeout));
+            return ExecuteAndWrapExceptionAsync(() => _channel.ConnectAsync().TimeoutAfter(timeout));
         }
 
-        public async Task DisconnectAsync(TimeSpan timeout)
+        public Task DisconnectAsync(TimeSpan timeout)
         {
-            _logger.Info<MqttChannelAdapter>("Disconnecting [Timeout={0}]", timeout);
+            _logger.Trace<MqttChannelAdapter>("Disconnecting [Timeout={0}]", timeout);
 
-            await ExecuteAndWrapExceptionAsync(() => _channel.DisconnectAsync().TimeoutAfter(timeout));
+            return ExecuteAndWrapExceptionAsync(() => _channel.DisconnectAsync().TimeoutAfter(timeout));
         }
 
-        public async Task SendPacketsAsync(TimeSpan timeout, CancellationToken cancellationToken, IEnumerable<MqttBasePacket> packets)
+        public Task SendPacketsAsync(TimeSpan timeout, CancellationToken cancellationToken, IEnumerable<MqttBasePacket> packets)
         {
-            await ExecuteAndWrapExceptionAsync(async () =>
+            return ExecuteAndWrapExceptionAsync(async () =>
             {
                 await _semaphore.WaitAsync(cancellationToken).ConfigureAwait(false);
                 try
@@ -60,8 +62,11 @@ namespace MQTTnet.Core.Adapter
 
                         _logger.Trace<MqttChannelAdapter>("TX >>> {0} [Timeout={1}]", packet, timeout);
 
-                        var writeBuffer = PacketSerializer.Serialize(packet);
+                        var chunks = PacketSerializer.Serialize(packet);
-                        await _channel.SendStream.WriteAsync(writeBuffer, 0, writeBuffer.Length, cancellationToken).ConfigureAwait(false);
+                        foreach (var chunk in chunks)
+                        {
+                            await _channel.SendStream.WriteAsync(chunk.Array, chunk.Offset, chunk.Count, cancellationToken).ConfigureAwait(false);
+                        }
                     }
 
                     if (timeout > TimeSpan.Zero)
@@ -102,7 +107,7 @@ namespace MQTTnet.Core.Adapter
                         throw new TaskCanceledException();
                     }
 
-                    packet = PacketSerializer.Deserialize(receivedMqttPacket);
+                    packet = PacketSerializer.Deserialize(receivedMqttPacket.Header, receivedMqttPacket.Body);
                     if (packet == null)
                     {
                         throw new MqttProtocolViolationException("Received malformed packet.");
@@ -114,14 +119,14 @@ namespace MQTTnet.Core.Adapter
                 {
                     receivedMqttPacket?.Dispose();
                 }
-            });
+            }).ConfigureAwait(false);
 
             return packet;
         }
 
         private static async Task<ReceivedMqttPacket> ReceiveAsync(Stream stream, CancellationToken cancellationToken)
         {
-            var header = MqttPacketReader.ReadHeaderFromSource(stream, cancellationToken);
+            var header = await MqttPacketReader.ReadHeaderAsync(stream, cancellationToken).ConfigureAwait(false);
             if (header == null)
             {
                 return null;
@@ -129,19 +134,36 @@ namespace MQTTnet.Core.Adapter
 
             if (header.BodyLength == 0)
             {
-                return new ReceivedMqttPacket(header, new MemoryStream(0));
+                return new ReceivedMqttPacket(header, new MemoryStream(new byte[0], false));
             }
 
-            var body = new byte[header.BodyLength];
+            var body = header.BodyLength <= ReadBufferSize ? new MemoryStream(header.BodyLength) : new MemoryStream();
-
+            
-            var offset = 0;
+            var buffer = new byte[ReadBufferSize];
-            do
+            while (body.Length < header.BodyLength)
             {
-                var readBytesCount = await stream.ReadAsync(body, offset, body.Length - offset, cancellationToken).ConfigureAwait(false);
+                var bytesLeft = header.BodyLength - (int)body.Length;
-                offset += readBytesCount;
+                if (bytesLeft > buffer.Length)
-            } while (offset < header.BodyLength);
+                {
+                    bytesLeft = buffer.Length;
+                }
 
-            return new ReceivedMqttPacket(header, new MemoryStream(body, 0, body.Length));
+                var readBytesCount = await stream.ReadAsync(buffer, 0, bytesLeft, cancellationToken).ConfigureAwait(false);
+                
+                // Check if the client closed the connection before sending the full body.
+                if (readBytesCount == 0)
+                {
+                    throw new MqttCommunicationException("Connection closed while reading remaining packet body.");
+                }
+
+                // Here is no need to await because internally only an array is used and no real I/O operation is made.
+                // Using async here will only generate overhead.
+                body.Write(buffer, 0, readBytesCount);
+            }
+
+            body.Seek(0L, SeekOrigin.Begin);
+            
+            return new ReceivedMqttPacket(header, body);
         }
 
         private static async Task ExecuteAndWrapExceptionAsync(Func<Task> action)
@@ -168,13 +190,25 @@ namespace MQTTnet.Core.Adapter
             }
             catch (COMException comException)
             {
-                if ((uint)comException.HResult == ErrorOperationAborted)
+                if ((uint) comException.HResult == ErrorOperationAborted)
                 {
                     throw new OperationCanceledException();
                 }
 
                 throw new MqttCommunicationException(comException);
             }
+            catch (IOException exception)
+            {
+                if (exception.InnerException is SocketException socketException)
+                {
+                    if (socketException.SocketErrorCode == SocketError.ConnectionAborted)
+                    {
+                        throw new OperationCanceledException();
+                    }
+                }
+
+                throw new MqttCommunicationException(exception);
+            }
             catch (Exception exception)
             {
                 throw new MqttCommunicationException(exception);

Frameworks/MQTTnet.NetStandard/Adapter/MqttChannelAdapterExtensions.cs

@@ -1,9 +1,9 @@
 using System;
 using System.Threading;
 using System.Threading.Tasks;
-using MQTTnet.Core.Packets;
+using MQTTnet.Packets;
 
-namespace MQTTnet.Core.Adapter
+namespace MQTTnet.Adapter
 {
     public static class MqttChannelAdapterExtensions
     {

Frameworks/MQTTnet.NetStandard/Adapter/MqttConnectingFailedException.cs

@@ -1,7 +1,7 @@
-using MQTTnet.Core.Exceptions;
+using MQTTnet.Exceptions;
-using MQTTnet.Core.Protocol;
+using MQTTnet.Protocol;
 
-namespace MQTTnet.Core.Adapter
+namespace MQTTnet.Adapter
 {
     public class MqttConnectingFailedException : MqttCommunicationException
     {

Frameworks/MQTTnet.NetStandard/Adapter/MqttServerAdapterClientAcceptedEventArgs.cs

@@ -1,7 +1,7 @@
 using System;
 using System.Threading.Tasks;
 
-namespace MQTTnet.Core.Adapter
+namespace MQTTnet.Adapter
 {
     public class MqttServerAdapterClientAcceptedEventArgs : EventArgs
     {

Frameworks/MQTTnet.NetStandard/Adapter/ReceivedMqttPacket.cs

@@ -1,8 +1,8 @@
 using System;
 using System.IO;
-using MQTTnet.Core.Packets;
+using MQTTnet.Packets;
 
-namespace MQTTnet.Core.Adapter
+namespace MQTTnet.Adapter
 {
     public sealed class ReceivedMqttPacket : IDisposable
     {

Frameworks/MQTTnet.NetStandard/ApplicationMessagePublisherExtensions.cs

@@ -1,7 +1,7 @@
 using System;
 using System.Threading.Tasks;
 
-namespace MQTTnet.Core
+namespace MQTTnet
 {
     public static class ApplicationMessagePublisherExtensions
     {

Frameworks/MQTTnet.NetStandard/Channel/IMqttChannel.cs

@@ -1,7 +1,7 @@
-using System.Threading.Tasks;
+using System.IO;
-using System.IO;
+using System.Threading.Tasks;
 
-namespace MQTTnet.Core.Channel
+namespace MQTTnet.Channel
 {
     public interface IMqttChannel
     {

Frameworks/MQTTnet.NetStandard/Client/IMqttClient.cs

@@ -1,11 +1,10 @@
 using System;
 using System.Collections.Generic;
 using System.Threading.Tasks;
-using MQTTnet.Core.Packets;
 
-namespace MQTTnet.Core.Client
+namespace MQTTnet.Client
 {
-    public interface IMqttClient : IApplicationMessageReceiver, IApplicationMessagePublisher
+    public interface IMqttClient : IApplicationMessageReceiver, IApplicationMessagePublisher, IDisposable
     {
         bool IsConnected { get; }
 
@@ -16,6 +15,6 @@ namespace MQTTnet.Core.Client
         Task DisconnectAsync();
 
         Task<IList<MqttSubscribeResult>> SubscribeAsync(IEnumerable<TopicFilter> topicFilters);
-        Task UnsubscribeAsync(IEnumerable<string> topicFilters);
+        Task UnsubscribeAsync(IEnumerable<string> topics);
     }
 }

Frameworks/MQTTnet.NetStandard/Client/IMqttClientAdapterFactory.cs

@@ -1,7 +1,7 @@
-using MQTTnet.Core.Adapter;
+using MQTTnet.Adapter;
-using MQTTnet.Core.Diagnostics;
+using MQTTnet.Diagnostics;
 
-namespace MQTTnet.Core.Client
+namespace MQTTnet.Client
 {
     public interface IMqttClientAdapterFactory
     {

Frameworks/MQTTnet.NetStandard/Client/IMqttClientChannelOptions.cs

@@ -1,4 +1,4 @@
-namespace MQTTnet.Core.Client
+namespace MQTTnet.Client
 {
     public interface IMqttClientChannelOptions
     {

Frameworks/MQTTnet.NetStandard/Client/IMqttClientCredentials.cs

@@ -1,4 +1,4 @@
-namespace MQTTnet.Core.Client
+namespace MQTTnet.Client
 {
     public interface IMqttClientCredentials
     {

Frameworks/MQTTnet.NetStandard/Client/IMqttClientFactory.cs

@@ -1,7 +1,7 @@
-using MQTTnet.Core.Diagnostics;
+using MQTTnet.Diagnostics;
-using MQTTnet.Core.ManagedClient;
+using MQTTnet.ManagedClient;
 
-namespace MQTTnet.Core.Client
+namespace MQTTnet.Client
 {
     public interface IMqttClientFactory
     {

Frameworks/MQTTnet.NetStandard/Client/IMqttClientOptions.cs

@@ -1,7 +1,7 @@
 using System;
-using MQTTnet.Core.Serializer;
+using MQTTnet.Serializer;
 
-namespace MQTTnet.Core.Client
+namespace MQTTnet.Client
 {
     public interface IMqttClientOptions
     {

Frameworks/MQTTnet.NetStandard/Client/MqttClient.cs

@@ -3,26 +3,24 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
-using MQTTnet.Core.Adapter;
+using MQTTnet.Adapter;
-using MQTTnet.Core.Diagnostics;
+using MQTTnet.Diagnostics;
-using MQTTnet.Core.Exceptions;
+using MQTTnet.Exceptions;
-using MQTTnet.Core.Internal;
+using MQTTnet.Internal;
-using MQTTnet.Core.Packets;
+using MQTTnet.Packets;
-using MQTTnet.Core.Protocol;
+using MQTTnet.Protocol;
 
-namespace MQTTnet.Core.Client
+namespace MQTTnet.Client
 {
     public class MqttClient : IMqttClient
     {
-        private readonly HashSet<ushort> _unacknowledgedPublishPackets = new HashSet<ushort>();
+        private readonly MqttPacketIdentifierProvider _packetIdentifierProvider = new MqttPacketIdentifierProvider();
-
         private readonly IMqttClientAdapterFactory _adapterFactory;
         private readonly MqttPacketDispatcher _packetDispatcher;
         private readonly IMqttNetLogger _logger;
 
         private IMqttClientOptions _options;
         private bool _isReceivingPackets;
-        private int _latestPacketIdentifier;
         private CancellationTokenSource _cancellationTokenSource;
         private IMqttChannelAdapter _adapter;
 
@@ -51,7 +49,7 @@ namespace MQTTnet.Core.Client
             {
                 _options = options;
                 _cancellationTokenSource = new CancellationTokenSource();
-                _latestPacketIdentifier = 0;
+                _packetIdentifierProvider.Reset();
                 _packetDispatcher.Reset();
 
                 _adapter = _adapterFactory.CreateClientAdapter(options.ChannelOptions, _logger);
@@ -77,7 +75,8 @@ namespace MQTTnet.Core.Client
             catch (Exception exception)
             {
                 _logger.Error<MqttClient>(exception, "Error while connecting with server.");
-                await DisconnectInternalAsync().ConfigureAwait(false);
+                await DisconnectInternalAsync(exception).ConfigureAwait(false);
+
                 throw;
             }
         }
@@ -95,7 +94,7 @@ namespace MQTTnet.Core.Client
             }
             finally
             {
-                await DisconnectInternalAsync().ConfigureAwait(false);
+                await DisconnectInternalAsync(null).ConfigureAwait(false);
             }
         }
 
@@ -107,7 +106,7 @@ namespace MQTTnet.Core.Client
 
             var subscribePacket = new MqttSubscribePacket
             {
-                PacketIdentifier = GetNewPacketIdentifier(),
+                PacketIdentifier = _packetIdentifierProvider.GetNewPacketIdentifier(),
                 TopicFilters = topicFilters.ToList()
             };
 
@@ -129,11 +128,11 @@ namespace MQTTnet.Core.Client
 
             var unsubscribePacket = new MqttUnsubscribePacket
             {
-                PacketIdentifier = GetNewPacketIdentifier(),
+                PacketIdentifier = _packetIdentifierProvider.GetNewPacketIdentifier(),
                 TopicFilters = topicFilters.ToList()
             };
 
-            await SendAndReceiveAsync<MqttUnsubAckPacket>(unsubscribePacket);
+            await SendAndReceiveAsync<MqttUnsubAckPacket>(unsubscribePacket).ConfigureAwait(false);
         }
 
         public async Task PublishAsync(IEnumerable<MqttApplicationMessage> applicationMessages)
@@ -141,23 +140,23 @@ namespace MQTTnet.Core.Client
             ThrowIfNotConnected();
 
             var publishPackets = applicationMessages.Select(m => m.ToPublishPacket());
+            var packetGroups = publishPackets.GroupBy(p => p.QualityOfServiceLevel).OrderBy(g => g.Key); 
 
-            foreach (var qosGroup in publishPackets.GroupBy(p => p.QualityOfServiceLevel))
+            foreach (var qosGroup in packetGroups)
             {
-                var qosPackets = qosGroup.ToArray();
                 switch (qosGroup.Key)
                 {
                     case MqttQualityOfServiceLevel.AtMostOnce:
                         {
                             // No packet identifier is used for QoS 0 [3.3.2.2 Packet Identifier]
-                            await _adapter.SendPacketsAsync(_options.CommunicationTimeout, _cancellationTokenSource.Token, qosPackets).ConfigureAwait(false);
+                            await _adapter.SendPacketsAsync(_options.CommunicationTimeout, _cancellationTokenSource.Token, qosGroup).ConfigureAwait(false);
                             break;
                         }
                     case MqttQualityOfServiceLevel.AtLeastOnce:
                         {
-                            foreach (var publishPacket in qosPackets)
+                            foreach (var publishPacket in qosGroup)
                             {
-                                publishPacket.PacketIdentifier = GetNewPacketIdentifier();
+                                publishPacket.PacketIdentifier = _packetIdentifierProvider.GetNewPacketIdentifier();
                                 await SendAndReceiveAsync<MqttPubAckPacket>(publishPacket).ConfigureAwait(false);
                             }
 
@@ -165,9 +164,9 @@ namespace MQTTnet.Core.Client
                         }
                     case MqttQualityOfServiceLevel.ExactlyOnce:
                         {
-                            foreach (var publishPacket in qosPackets)
+                            foreach (var publishPacket in qosGroup)
                             {
-                                publishPacket.PacketIdentifier = GetNewPacketIdentifier();
+                                publishPacket.PacketIdentifier = _packetIdentifierProvider.GetNewPacketIdentifier();
                                 var pubRecPacket = await SendAndReceiveAsync<MqttPubRecPacket>(publishPacket).ConfigureAwait(false);
                                 await SendAndReceiveAsync<MqttPubCompPacket>(pubRecPacket.CreateResponse<MqttPubRelPacket>()).ConfigureAwait(false);
                             }
@@ -182,6 +181,11 @@ namespace MQTTnet.Core.Client
             }
         }
 
+        public void Dispose()
+        {
+            _cancellationTokenSource?.Dispose();
+        }
+
         private async Task<MqttConnAckPacket> AuthenticateAsync(MqttApplicationMessage willApplicationMessage)
         {
             var connectPacket = new MqttConnectPacket
@@ -213,7 +217,7 @@ namespace MQTTnet.Core.Client
             if (IsConnected) throw new MqttProtocolViolationException(message);
         }
 
-        private async Task DisconnectInternalAsync()
+        private async Task DisconnectInternalAsync(Exception exception)
         {
             var clientWasConnected = IsConnected;
             IsConnected = false;
@@ -233,14 +237,14 @@ namespace MQTTnet.Core.Client
                 await _adapter.DisconnectAsync(_options.CommunicationTimeout).ConfigureAwait(false);
                 _logger.Info<MqttClient>("Disconnected from adapter.");
             }
-            catch (Exception exception)
+            catch (Exception adapterException)
             {
-                _logger.Warning<MqttClient>(exception, "Error while disconnecting from adapter.");
+                _logger.Warning<MqttClient>(adapterException, "Error while disconnecting from adapter.");
             }
             finally
             {
                 _logger.Info<MqttClient>("Disconnected.");
-                Disconnected?.Invoke(this, new MqttClientDisconnectedEventArgs(clientWasConnected));
+                Disconnected?.Invoke(this, new MqttClientDisconnectedEventArgs(clientWasConnected, exception));
             }
         }
 
@@ -249,28 +253,28 @@ namespace MQTTnet.Core.Client
             try
             {
                 _logger.Info<MqttClient>("Received <<< {0}", packet);
+                
+                if (packet is MqttPublishPacket publishPacket)
+                {
+                    await ProcessReceivedPublishPacketAsync(publishPacket).ConfigureAwait(false);
+                    return;
+                }
 
                 if (packet is MqttPingReqPacket)
                 {
-                    await SendAsync(new MqttPingRespPacket());
+                    await SendAsync(new MqttPingRespPacket()).ConfigureAwait(false);
                     return;
                 }
 
                 if (packet is MqttDisconnectPacket)
                 {
-                    await DisconnectAsync();
+                    await DisconnectAsync().ConfigureAwait(false);
-                    return;
-                }
-
-                if (packet is MqttPublishPacket publishPacket)
-                {
-                    await ProcessReceivedPublishPacket(publishPacket);
                     return;
                 }
 
                 if (packet is MqttPubRelPacket pubRelPacket)
                 {
-                    await ProcessReceivedPubRelPacket(pubRelPacket);
+                    await ProcessReceivedPubRelPacket(pubRelPacket).ConfigureAwait(false);
                     return;
                 }
 
@@ -295,32 +299,25 @@ namespace MQTTnet.Core.Client
             }
         }
 
-        private async Task ProcessReceivedPublishPacket(MqttPublishPacket publishPacket)
+        private Task ProcessReceivedPublishPacketAsync(MqttPublishPacket publishPacket)
         {
             if (publishPacket.QualityOfServiceLevel == MqttQualityOfServiceLevel.AtMostOnce)
             {
                 FireApplicationMessageReceivedEvent(publishPacket);
-                return;
+                return Task.FromResult(0);
             }
 
             if (publishPacket.QualityOfServiceLevel == MqttQualityOfServiceLevel.AtLeastOnce)
             {
                 FireApplicationMessageReceivedEvent(publishPacket);
-                await SendAsync(new MqttPubAckPacket { PacketIdentifier = publishPacket.PacketIdentifier });
+                return SendAsync(new MqttPubAckPacket { PacketIdentifier = publishPacket.PacketIdentifier });
-                return;
             }
 
             if (publishPacket.QualityOfServiceLevel == MqttQualityOfServiceLevel.ExactlyOnce)
             {
                 // QoS 2 is implement as method "B" [4.3.3 QoS 2: Exactly once delivery]
-                lock (_unacknowledgedPublishPackets)
-                {
-                    _unacknowledgedPublishPackets.Add(publishPacket.PacketIdentifier);
-                }
-
                 FireApplicationMessageReceivedEvent(publishPacket);
-                await SendAsync(new MqttPubRecPacket { PacketIdentifier = publishPacket.PacketIdentifier });
+                return SendAsync(new MqttPubRecPacket { PacketIdentifier = publishPacket.PacketIdentifier });
-                return;
             }
 
             throw new MqttCommunicationException("Received a not supported QoS level.");
@@ -328,11 +325,6 @@ namespace MQTTnet.Core.Client
 
         private Task ProcessReceivedPubRelPacket(MqttPubRelPacket pubRelPacket)
         {
-            lock (_unacknowledgedPublishPackets)
-            {
-                _unacknowledgedPublishPackets.Remove(pubRelPacket.PacketIdentifier);
-            }
-
             return SendAsync(pubRelPacket.CreateResponse<MqttPubCompPacket>());
         }
 
@@ -348,11 +340,6 @@ namespace MQTTnet.Core.Client
             return (TResponsePacket)await packetAwaiter.ConfigureAwait(false);
         }
 
-        private ushort GetNewPacketIdentifier()
-        {
-            return (ushort)Interlocked.Increment(ref _latestPacketIdentifier);
-        }
-
         private async Task SendKeepAliveMessagesAsync(CancellationToken cancellationToken)
         {
             _logger.Info<MqttClient>("Start sending keep alive packets.");
@@ -361,13 +348,8 @@ namespace MQTTnet.Core.Client
             {
                 while (!cancellationToken.IsCancellationRequested)
                 {
-                    await Task.Delay(_options.KeepAlivePeriod, cancellationToken).ConfigureAwait(false);
-                    if (cancellationToken.IsCancellationRequested)
-                    {
-                        return;
-                    }
-
                     await SendAndReceiveAsync<MqttPingRespPacket>(new MqttPingReqPacket()).ConfigureAwait(false);
+                    await Task.Delay(_options.KeepAlivePeriod, cancellationToken).ConfigureAwait(false);
                 }
             }
             catch (OperationCanceledException)
@@ -377,7 +359,7 @@ namespace MQTTnet.Core.Client
                     return;
                 }
 
-                await DisconnectInternalAsync().ConfigureAwait(false);
+                await DisconnectInternalAsync(null).ConfigureAwait(false);
             }
             catch (MqttCommunicationException exception)
             {
@@ -387,12 +369,12 @@ namespace MQTTnet.Core.Client
                 }
 
                 _logger.Warning<MqttClient>(exception, "MQTT communication exception while sending/receiving keep alive packets.");
-                await DisconnectInternalAsync().ConfigureAwait(false);
+                await DisconnectInternalAsync(exception).ConfigureAwait(false);
             }
             catch (Exception exception)
             {
                 _logger.Warning<MqttClient>(exception, "Unhandled exception while sending/receiving keep alive packets.");
-                await DisconnectInternalAsync().ConfigureAwait(false);
+                await DisconnectInternalAsync(exception).ConfigureAwait(false);
             }
             finally
             {
@@ -427,7 +409,7 @@ namespace MQTTnet.Core.Client
                     return;
                 }
 
-                await DisconnectInternalAsync().ConfigureAwait(false);
+                await DisconnectInternalAsync(null).ConfigureAwait(false);
             }
             catch (MqttCommunicationException exception)
             {
@@ -437,12 +419,12 @@ namespace MQTTnet.Core.Client
                 }
 
                 _logger.Warning<MqttClient>(exception, "MQTT communication exception while receiving packets.");
-                await DisconnectInternalAsync().ConfigureAwait(false);
+                await DisconnectInternalAsync(exception).ConfigureAwait(false);
             }
             catch (Exception exception)
             {
                 _logger.Error<MqttClient>(exception, "Unhandled exception while receiving packets.");
-                await DisconnectInternalAsync().ConfigureAwait(false);
+                await DisconnectInternalAsync(exception).ConfigureAwait(false);
             }
             finally
             {
@@ -454,7 +436,7 @@ namespace MQTTnet.Core.Client
         {
 #pragma warning disable CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
             Task.Run(
-                () => ProcessReceivedPacketAsync(packet),
+                async () => await ProcessReceivedPacketAsync(packet).ConfigureAwait(false),
                 cancellationToken).ConfigureAwait(false);
 #pragma warning restore CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
         }
@@ -465,7 +447,7 @@ namespace MQTTnet.Core.Client
 
 #pragma warning disable CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
             Task.Run(
-                async () => await ReceivePacketsAsync(cancellationToken),
+                async () => await ReceivePacketsAsync(cancellationToken).ConfigureAwait(false),
                 cancellationToken).ConfigureAwait(false);
 #pragma warning restore CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
 
@@ -479,7 +461,7 @@ namespace MQTTnet.Core.Client
         {
 #pragma warning disable CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
             Task.Run(
-                async () => await SendKeepAliveMessagesAsync(cancellationToken), 
+                async () => await SendKeepAliveMessagesAsync(cancellationToken).ConfigureAwait(false), 
                 cancellationToken).ConfigureAwait(false);
 #pragma warning restore CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
         }

Frameworks/MQTTnet.NetStandard/Client/MqttClientConnectResult.cs

@@ -1,4 +1,4 @@
-namespace MQTTnet.Core.Client
+namespace MQTTnet.Client
 {
     public class MqttClientConnectResult
     {

Frameworks/MQTTnet.NetStandard/Client/MqttClientConnectedEventArgs.cs

@@ -1,6 +1,6 @@
 using System;
 
-namespace MQTTnet.Core.Client
+namespace MQTTnet.Client
 {
     public class MqttClientConnectedEventArgs : EventArgs
     {

Frameworks/MQTTnet.NetStandard/Client/MqttClientCredentials.cs

@@ -1,4 +1,4 @@
-namespace MQTTnet.Core.Client
+namespace MQTTnet.Client
 {
     public class MqttClientCredentials : IMqttClientCredentials
     {

Frameworks/MQTTnet.NetStandard/Client/MqttClientDisconnectedEventArgs.cs

@@ -1,14 +1,17 @@
 using System;
 
-namespace MQTTnet.Core.Client
+namespace MQTTnet.Client
 {
     public class MqttClientDisconnectedEventArgs : EventArgs
     {
-        public MqttClientDisconnectedEventArgs(bool clientWasConnected)
+        public MqttClientDisconnectedEventArgs(bool clientWasConnected, Exception exception)
         {
             ClientWasConnected = clientWasConnected;
+            Exception = exception;
         }
 
         public bool ClientWasConnected { get; }
+
+        public Exception Exception { get; }
     }
 }

Frameworks/MQTTnet.NetStandard/Client/MqttClientExtensions.cs

@@ -2,8 +2,9 @@
 using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
+using MQTTnet.Protocol;
 
-namespace MQTTnet.Core.Client
+namespace MQTTnet.Client
 {
     public static class MqttClientExtensions
     {
@@ -15,6 +16,14 @@ namespace MQTTnet.Core.Client
             return client.SubscribeAsync(topicFilters.ToList());
         }
 
+        public static Task<IList<MqttSubscribeResult>> SubscribeAsync(this IMqttClient client, string topic, MqttQualityOfServiceLevel qualityOfServiceLevel)
+        {
+            if (client == null) throw new ArgumentNullException(nameof(client));
+            if (topic == null) throw new ArgumentNullException(nameof(topic));
+
+            return client.SubscribeAsync(new TopicFilterBuilder().WithTopic(topic).WithQualityOfServiceLevel(qualityOfServiceLevel).Build());
+        }
+
         public static Task UnsubscribeAsync(this IMqttClient client, params string[] topicFilters)
         {
             if (client == null) throw new ArgumentNullException(nameof(client));

Frameworks/MQTTnet.NetStandard/Client/MqttClientOptions.cs

@@ -1,7 +1,7 @@
 using System;
-using MQTTnet.Core.Serializer;
+using MQTTnet.Serializer;
 
-namespace MQTTnet.Core.Client
+namespace MQTTnet.Client
 {
     public class MqttClientOptions : IMqttClientOptions
     {

Frameworks/MQTTnet.NetStandard/Client/MqttClientOptionsBuilder.cs

@@ -1,8 +1,8 @@
 using System;
 using System.Linq;
-using MQTTnet.Core.Serializer;
+using MQTTnet.Serializer;
 
-namespace MQTTnet.Core.Client
+namespace MQTTnet.Client
 {
     public class MqttClientOptionsBuilder
     {
@@ -119,11 +119,11 @@ namespace MQTTnet.Core.Client
 
                 if (_tcpOptions != null)
                 {
-                    _options.ChannelOptions = _tcpOptions;
+                    _tcpOptions.TlsOptions = _tlsOptions;
                 }
-                else
+                else if (_webSocketOptions != null)
                 {
-                    _options.ChannelOptions = _webSocketOptions;
+                    _webSocketOptions.TlsOptions = _tlsOptions;
                 }
             }
 

Frameworks/MQTTnet.NetStandard/Client/MqttClientTcpOptions.cs

@@ -1,4 +1,4 @@
-namespace MQTTnet.Core.Client
+namespace MQTTnet.Client
 {
     public class MqttClientTcpOptions : IMqttClientChannelOptions
     {

Frameworks/MQTTnet.NetStandard/Client/MqttClientTcpOptionsExtensions.cs

@@ -1,6 +1,6 @@
 using System;
 
-namespace MQTTnet.Core.Client
+namespace MQTTnet.Client
 {
     public static class MqttClientTcpOptionsExtensions
     {

Frameworks/MQTTnet.NetStandard/Client/MqttClientTlsOptions.cs

@@ -1,6 +1,6 @@
 using System.Collections.Generic;
 
-namespace MQTTnet.Core.Client
+namespace MQTTnet.Client
 {
     public class MqttClientTlsOptions
     {

Frameworks/MQTTnet.NetStandard/Client/MqttClientWebSocketOptions.cs

@@ -1,7 +1,7 @@
 using System.Collections.Generic;
 using System.Net;
 
-namespace MQTTnet.Core.Client
+namespace MQTTnet.Client
 {
     public class MqttClientWebSocketOptions : IMqttClientChannelOptions
     {

Frameworks/MQTTnet.NetStandard/Client/MqttPacketDispatcher.cs

@@ -1,12 +1,12 @@
 using System;
 using System.Collections.Concurrent;
 using System.Threading.Tasks;
-using MQTTnet.Core.Diagnostics;
+using MQTTnet.Diagnostics;
-using MQTTnet.Core.Exceptions;
+using MQTTnet.Exceptions;
-using MQTTnet.Core.Internal;
+using MQTTnet.Internal;
-using MQTTnet.Core.Packets;
+using MQTTnet.Packets;
 
-namespace MQTTnet.Core.Client
+namespace MQTTnet.Client
 {
     public class MqttPacketDispatcher
     {
@@ -83,7 +83,7 @@ namespace MQTTnet.Core.Client
             {
                 _packetByResponseType[responseType] = tcs;
             }
-
+            
             return tcs;
         }
 

Frameworks/MQTTnet.NetStandard/Client/MqttPacketIdentifierProvider.cs

@@ -0,0 +1,32 @@
+namespace MQTTnet.Client
+{
+    public class MqttPacketIdentifierProvider
+    {
+        private readonly object _syncRoot = new object();
+        private ushort _value;
+
+        public void Reset()
+        {
+            lock (_syncRoot)
+            {
+                _value = 0;
+            }
+        }
+
+        public ushort GetNewPacketIdentifier()
+        {
+            lock (_syncRoot)
+            {
+                _value++;
+
+                if (_value == 0)
+                {
+                    // As per official MQTT documentation the package identifier should never be 0.
+                    _value = 1;
+                }
+
+                return _value;
+            }
+        }
+    }
+}

Frameworks/MQTTnet.NetStandard/Client/MqttSubscribeResult.cs

@@ -1,7 +1,6 @@
-using MQTTnet.Core.Packets;
+using MQTTnet.Protocol;
-using MQTTnet.Core.Protocol;
 
-namespace MQTTnet.Core.Client
+namespace MQTTnet.Client
 {
     public class MqttSubscribeResult
     {

Frameworks/MQTTnet.NetStandard/Diagnostics/IMqttNetLogger.cs

@@ -1,6 +1,6 @@
 using System;
 
-namespace MQTTnet.Core.Diagnostics
+namespace MQTTnet.Diagnostics
 {
     public interface IMqttNetLogger
     {

Frameworks/MQTTnet.NetStandard/Diagnostics/MqttNetConsoleLogger.cs

@@ -1,50 +0,0 @@
-using System;
-using System.Text;
-using MQTTnet.Core.Diagnostics;
-
-namespace MQTTnet.Diagnostics
-{
-    public static class MqttNetConsoleLogger
-    {
-        private static readonly object Lock = new object();
-
-        public static void ForwardToConsole()
-        {
-            MqttNetGlobalLog.LogMessagePublished -= PrintToConsole;
-            MqttNetGlobalLog.LogMessagePublished += PrintToConsole;
-        }
-
-        private static void PrintToConsole(object sender, MqttNetLogMessagePublishedEventArgs e)
-        {
-            var output = new StringBuilder();
-            output.AppendLine($">> [{e.TraceMessage.Timestamp:O}] [{e.TraceMessage.ThreadId}] [{e.TraceMessage.Source}] [{e.TraceMessage.Level}]: {e.TraceMessage.Message}");
-            if (e.TraceMessage.Exception != null)
-            {
-                output.AppendLine(e.TraceMessage.Exception.ToString());
-            }
-
-            lock (Lock)
-            {
-                var backupColor = Console.ForegroundColor;
-                switch (e.TraceMessage.Level)
-                {
-                    case MqttNetLogLevel.Error:
-                        Console.ForegroundColor = ConsoleColor.Red;
-                        break;
-                    case MqttNetLogLevel.Warning:
-                        Console.ForegroundColor = ConsoleColor.Yellow;
-                        break;
-                    case MqttNetLogLevel.Info:
-                        Console.ForegroundColor = ConsoleColor.Green;
-                        break;
-                    case MqttNetLogLevel.Verbose:
-                        Console.ForegroundColor = ConsoleColor.Gray;
-                        break;
-                }
-
-                Console.Write(output);
-                Console.ForegroundColor = backupColor;
-            }
-        }
-    }
-}

Frameworks/MQTTnet.NetStandard/Diagnostics/MqttNetGlobalLogger.cs

@@ -1,8 +1,8 @@
 using System;
 
-namespace MQTTnet.Core.Diagnostics
+namespace MQTTnet.Diagnostics
 {
-    public static class MqttNetGlobalLog
+    public static class MqttNetGlobalLogger
     {
         public static event EventHandler<MqttNetLogMessagePublishedEventArgs> LogMessagePublished;
 

Frameworks/MQTTnet.NetStandard/Diagnostics/MqttNetLogLevel.cs

@@ -1,4 +1,4 @@
-namespace MQTTnet.Core.Diagnostics
+namespace MQTTnet.Diagnostics
 {
     public enum MqttNetLogLevel
     {

Frameworks/MQTTnet.NetStandard/Diagnostics/MqttNetLogMessage.cs

@@ -1,6 +1,6 @@
 using System;
 
-namespace MQTTnet.Core.Diagnostics
+namespace MQTTnet.Diagnostics
 {
     public sealed class MqttNetLogMessage
     {

Frameworks/MQTTnet.NetStandard/Diagnostics/MqttNetLogMessagePublishedEventArgs.cs

@@ -1,6 +1,6 @@
 using System;
 
-namespace MQTTnet.Core.Diagnostics
+namespace MQTTnet.Diagnostics
 {
     public sealed class MqttNetLogMessagePublishedEventArgs : EventArgs
     {

Frameworks/MQTTnet.NetStandard/Diagnostics/MqttNetLogger.cs

@@ -1,6 +1,6 @@
 using System;
 
-namespace MQTTnet.Core.Diagnostics
+namespace MQTTnet.Diagnostics
 {
     public class MqttNetLogger : IMqttNetLogger
     {
@@ -10,7 +10,7 @@ namespace MQTTnet.Core.Diagnostics
         {
             _logId = logId;
         }
-        
+
         public event EventHandler<MqttNetLogMessagePublishedEventArgs> LogMessagePublished;
 
         public void Trace<TSource>(string message, params object[] parameters)
@@ -46,7 +46,7 @@ namespace MQTTnet.Core.Diagnostics
         private void Publish<TSource>(MqttNetLogLevel logLevel, Exception exception, string message, object[] parameters)
         {
             var hasLocalListeners = LogMessagePublished != null;
-            var hasGlobalListeners = MqttNetGlobalLog.HasListeners;
+            var hasGlobalListeners = MqttNetGlobalLogger.HasListeners;
 
             if (!hasLocalListeners && !hasGlobalListeners)
             {
@@ -62,7 +62,7 @@ namespace MQTTnet.Core.Diagnostics
 
             if (hasGlobalListeners)
             {
-                MqttNetGlobalLog.Publish(traceMessage);
+                MqttNetGlobalLogger.Publish(traceMessage);
             }
 
             if (hasLocalListeners)

Frameworks/MQTTnet.NetStandard/Diagnostics/TargetFrameworkInfoProvider.cs

@@ -1,4 +1,4 @@
-namespace MQTTnet
+namespace MQTTnet.Diagnostics
 {
     public static class TargetFrameworkInfoProvider
     {

Frameworks/MQTTnet.NetStandard/Exceptions/MqttCommunicationException.cs

@@ -1,6 +1,6 @@
 using System;
 
-namespace MQTTnet.Core.Exceptions
+namespace MQTTnet.Exceptions
 {
     public class MqttCommunicationException : Exception
     {

Frameworks/MQTTnet.NetStandard/Exceptions/MqttCommunicationTimedOutException.cs

@@ -1,4 +1,4 @@
-namespace MQTTnet.Core.Exceptions
+namespace MQTTnet.Exceptions
 {
     public sealed class MqttCommunicationTimedOutException : MqttCommunicationException
     {

Frameworks/MQTTnet.NetStandard/Exceptions/MqttProtocolViolationException.cs

@@ -1,6 +1,6 @@
 using System;
 
-namespace MQTTnet.Core.Exceptions
+namespace MQTTnet.Exceptions
 {
     public sealed class MqttProtocolViolationException : Exception
     {

Frameworks/MQTTnet.NetStandard/IApplicationMessagePublisher.cs

@@ -1,7 +1,7 @@
 using System.Collections.Generic;
 using System.Threading.Tasks;
 
-namespace MQTTnet.Core
+namespace MQTTnet
 {
     public interface IApplicationMessagePublisher
     {

Frameworks/MQTTnet.NetStandard/IApplicationMessageReceiver.cs

@@ -1,7 +1,6 @@
 using System;
-using MQTTnet.Core.Client;
 
-namespace MQTTnet.Core
+namespace MQTTnet
 {
     public interface IApplicationMessageReceiver
     {

Frameworks/MQTTnet.NetStandard/Implementations/MqttClientAdapterFactory.cs

@@ -1,8 +1,8 @@
 using System;
-using MQTTnet.Core.Adapter;
+using MQTTnet.Adapter;
-using MQTTnet.Core.Client;
+using MQTTnet.Client;
-using MQTTnet.Core.Diagnostics;
+using MQTTnet.Diagnostics;
-using MQTTnet.Core.Serializer;
+using MQTTnet.Serializer;
 
 namespace MQTTnet.Implementations
 {

Frameworks/MQTTnet.NetStandard/Implementations/MqttServerAdapter.Uwp.cs

@@ -1,11 +1,11 @@
 #if WINDOWS_UWP
 using System;
 using System.Threading.Tasks;
-using MQTTnet.Core.Adapter;
-using MQTTnet.Core.Server;
 using Windows.Networking.Sockets;
-using MQTTnet.Core.Diagnostics;
+using MQTTnet.Adapter;
-using MQTTnet.Core.Serializer;
+using MQTTnet.Diagnostics;
+using MQTTnet.Serializer;
+using MQTTnet.Server;
 
 namespace MQTTnet.Implementations
 {
@@ -21,7 +21,7 @@ namespace MQTTnet.Implementations
 
         public event EventHandler<MqttServerAdapterClientAcceptedEventArgs> ClientAccepted;
 
-        public async Task StartAsync(MqttServerOptions options)
+        public async Task StartAsync(IMqttServerOptions options)
         {
             if (options == null) throw new ArgumentNullException(nameof(options));
 

Frameworks/MQTTnet.NetStandard/Implementations/MqttServerAdapter.cs

@@ -7,10 +7,10 @@ using System.Security.Authentication;
 using System.Security.Cryptography.X509Certificates;
 using System.Threading;
 using System.Threading.Tasks;
-using MQTTnet.Core.Adapter;
+using MQTTnet.Adapter;
-using MQTTnet.Core.Server;
+using MQTTnet.Diagnostics;
-using MQTTnet.Core.Diagnostics;
+using MQTTnet.Serializer;
-using MQTTnet.Core.Serializer;
+using MQTTnet.Server;
 
 namespace MQTTnet.Implementations
 {
@@ -30,7 +30,7 @@ namespace MQTTnet.Implementations
 
         public event EventHandler<MqttServerAdapterClientAcceptedEventArgs> ClientAccepted;
 
-        public Task StartAsync(MqttServerOptions options)
+        public Task StartAsync(IMqttServerOptions options)
         {
             if (_cancellationTokenSource != null) throw new InvalidOperationException("Server is already started.");
 
@@ -39,10 +39,10 @@ namespace MQTTnet.Implementations
             if (options.DefaultEndpointOptions.IsEnabled)
             {
                 _defaultEndpointSocket = new Socket(SocketType.Stream, ProtocolType.Tcp);
-                _defaultEndpointSocket.Bind(new IPEndPoint(IPAddress.Any, options.GetDefaultEndpointPort()));
+                _defaultEndpointSocket.Bind(new IPEndPoint(options.DefaultEndpointOptions.BoundIPAddress, options.GetDefaultEndpointPort()));
                 _defaultEndpointSocket.Listen(options.ConnectionBacklog);
 
-                Task.Run(() => AcceptDefaultEndpointConnectionsAsync(_cancellationTokenSource.Token), _cancellationTokenSource.Token);
+                Task.Run(async () => await AcceptDefaultEndpointConnectionsAsync(_cancellationTokenSource.Token).ConfigureAwait(false), _cancellationTokenSource.Token).ConfigureAwait(false);
             }
 
             if (options.TlsEndpointOptions.IsEnabled)
@@ -59,10 +59,10 @@ namespace MQTTnet.Implementations
                 }
 
                 _tlsEndpointSocket = new Socket(SocketType.Stream, ProtocolType.Tcp);
-                _tlsEndpointSocket.Bind(new IPEndPoint(IPAddress.Any, options.GetTlsEndpointPort()));
+                _tlsEndpointSocket.Bind(new IPEndPoint(options.TlsEndpointOptions.BoundIPAddress, options.GetTlsEndpointPort()));
                 _tlsEndpointSocket.Listen(options.ConnectionBacklog);
 
-                Task.Run(() => AcceptTlsEndpointConnectionsAsync(_cancellationTokenSource.Token), _cancellationTokenSource.Token);
+                Task.Run(async () => await AcceptTlsEndpointConnectionsAsync(_cancellationTokenSource.Token).ConfigureAwait(false), _cancellationTokenSource.Token).ConfigureAwait(false);
             }
 
             return Task.FromResult(0);
@@ -102,14 +102,22 @@ namespace MQTTnet.Implementations
 #else
                     var clientSocket = await _defaultEndpointSocket.AcceptAsync().ConfigureAwait(false);
 #endif
+
                     var clientAdapter = new MqttChannelAdapter(new MqttTcpChannel(clientSocket, null), new MqttPacketSerializer(), _logger);
                     ClientAccepted?.Invoke(this, new MqttServerAdapterClientAcceptedEventArgs(clientAdapter));
                 }
+                catch (ObjectDisposedException)
+                {
+                    // It can happen that the listener socket is accessed after the cancellation token is already set and the listener socket is disposed.
+                }
                 catch (Exception exception)
                 {
-                    _logger.Error<MqttServerAdapter>(exception, "Error while accepting connection at default endpoint.");
+                    if (exception is SocketException s && s.SocketErrorCode == SocketError.OperationAborted)
+                    {
+                        return;
+                    }
 
-                    //excessive CPU consumed if in endless loop of socket errors
+                    _logger.Error<MqttServerAdapter>(exception, "Error while accepting connection at default endpoint.");
                     await Task.Delay(TimeSpan.FromSeconds(1), cancellationToken).ConfigureAwait(false);
                 }
             }
@@ -129,15 +137,22 @@ namespace MQTTnet.Implementations
 
                     var sslStream = new SslStream(new NetworkStream(clientSocket));
                     await sslStream.AuthenticateAsServerAsync(_tlsCertificate, false, SslProtocols.Tls12, false).ConfigureAwait(false);
-
+                    
                     var clientAdapter = new MqttChannelAdapter(new MqttTcpChannel(clientSocket, sslStream), new MqttPacketSerializer(), _logger);
                     ClientAccepted?.Invoke(this, new MqttServerAdapterClientAcceptedEventArgs(clientAdapter));
                 }
+                catch (ObjectDisposedException)
+                {
+                    // It can happen that the listener socket is accessed after the cancellation token is already set and the listener socket is disposed.
+                }
                 catch (Exception exception)
                 {
-                    _logger.Error<MqttServerAdapter>(exception, "Error while accepting connection at TLS endpoint.");
+                    if (exception is SocketException s && s.SocketErrorCode == SocketError.OperationAborted)
+                    {
+                        return;
+                    }
 
-                    //excessive CPU consumed if in endless loop of socket errors
+                    _logger.Error<MqttServerAdapter>(exception, "Error while accepting connection at TLS endpoint.");
                     await Task.Delay(TimeSpan.FromSeconds(1), cancellationToken).ConfigureAwait(false);
                 }
             }

Frameworks/MQTTnet.NetStandard/Implementations/MqttTcpChannel.Uwp.cs

@@ -8,8 +8,8 @@ using System.Threading.Tasks;
 using Windows.Networking;
 using Windows.Networking.Sockets;
 using Windows.Security.Cryptography.Certificates;
-using MQTTnet.Core.Channel;
+using MQTTnet.Channel;
-using MQTTnet.Core.Client;
+using MQTTnet.Client;
 
 namespace MQTTnet.Implementations
 {

Frameworks/MQTTnet.NetStandard/Implementations/MqttTcpChannel.cs

@@ -5,10 +5,10 @@ using System.Net.Sockets;
 using System.Security.Authentication;
 using System.Security.Cryptography.X509Certificates;
 using System.Threading.Tasks;
-using MQTTnet.Core.Channel;
-using MQTTnet.Core.Client;
 using System.IO;
 using System.Linq;
+using MQTTnet.Channel;
+using MQTTnet.Client;
 
 namespace MQTTnet.Implementations
 {
@@ -70,7 +70,7 @@ namespace MQTTnet.Implementations
                 _sslStream = new SslStream(new NetworkStream(_socket, true), false, InternalUserCertificateValidationCallback);
                 await _sslStream.AuthenticateAsClientAsync(_options.Server, LoadCertificates(_options), SslProtocols.Tls12, _options.TlsOptions.IgnoreCertificateRevocationErrors).ConfigureAwait(false);
             }
-
+            
             CreateStreams(_socket, _sslStream);
         }
 
@@ -130,7 +130,7 @@ namespace MQTTnet.Implementations
 
             foreach (var certificate in options.TlsOptions.Certificates)
             {
-                certificates.Add(new X509Certificate(certificate));
+                certificates.Add(new X509Certificate2(certificate));
             }
 
             return certificates;
@@ -139,10 +139,7 @@ namespace MQTTnet.Implementations
         private void CreateStreams(Socket socket, Stream sslStream)
         {
             var stream = sslStream ?? new NetworkStream(socket);
-
+            
-            //cannot use this as default buffering prevents from receiving the first connect message
-            //need two streams otherwise read and write have to be synchronized
-
             //todo: if branch can be used with min dependency NetStandard1.6
 #if NET452 || NET461
             SendStream = new BufferedStream(stream, BufferSize);
@@ -155,4 +152,4 @@ namespace MQTTnet.Implementations
 
     }
 }
-#endif
+#endif

Frameworks/MQTTnet.NetStandard/Implementations/MqttWebSocketChannel.cs

@@ -1,11 +1,11 @@
-using MQTTnet.Core.Channel;
+using System;
-using MQTTnet.Core.Client;
-using System;
 using System.IO;
 using System.Net.WebSockets;
 using System.Security.Cryptography.X509Certificates;
 using System.Threading;
 using System.Threading.Tasks;
+using MQTTnet.Channel;
+using MQTTnet.Client;
 
 namespace MQTTnet.Implementations
 {

Frameworks/MQTTnet.NetStandard/Implementations/WebSocketStream.cs

@@ -5,7 +5,7 @@ using System.Linq;
 using System.Net.WebSockets;
 using System.Threading;
 using System.Threading.Tasks;
-using MQTTnet.Core.Exceptions;
+using MQTTnet.Exceptions;
 
 namespace MQTTnet.Implementations
 {

Frameworks/MQTTnet.NetStandard/Internal/MqttApplicationMessageExtensions.cs

@@ -1,6 +1,6 @@
-using MQTTnet.Core.Packets;
+using MQTTnet.Packets;
 
-namespace MQTTnet.Core.Internal
+namespace MQTTnet.Internal
 {
     internal static class MqttApplicationMessageExtensions
     {

Frameworks/MQTTnet.NetStandard/Internal/TaskExtensions.cs

@@ -1,21 +1,23 @@
 using System;
 using System.Threading;
 using System.Threading.Tasks;
-using MQTTnet.Core.Exceptions;
+using MQTTnet.Exceptions;
 
-namespace MQTTnet.Core.Internal
+namespace MQTTnet.Internal
 {
     public static class TaskExtensions
     {
         public static async Task TimeoutAfter(this Task task, TimeSpan timeout)
         {
-            using (var cancellationTokenSource = new CancellationTokenSource())
+            if (task == null) throw new ArgumentNullException(nameof(task));
+
+            using (var timeoutCts = new CancellationTokenSource())
             {
                 try
                 {
-                    var timeoutTask = Task.Delay(timeout, cancellationTokenSource.Token);
+                    var timeoutTask = Task.Delay(timeout, timeoutCts.Token);
                     var finishedTask = await Task.WhenAny(timeoutTask, task).ConfigureAwait(false);
-
+                    
                     if (finishedTask == timeoutTask)
                     {
                         throw new MqttCommunicationTimedOutException();
@@ -28,23 +30,25 @@ namespace MQTTnet.Core.Internal
 
                     if (task.IsFaulted)
                     {
-                        throw new MqttCommunicationException(task.Exception.GetBaseException());
+                        throw new MqttCommunicationException(task.Exception?.GetBaseException());
                     }
                 }
                 finally
                 {
-                    cancellationTokenSource.Cancel();
+                    timeoutCts.Cancel();
                 }
             }
         }
 
         public static async Task<TResult> TimeoutAfter<TResult>(this Task<TResult> task, TimeSpan timeout)
         {
-            using (var cancellationTokenSource = new CancellationTokenSource())
+            if (task == null) throw new ArgumentNullException(nameof(task));
+
+            using (var timeoutCts = new CancellationTokenSource())
             {
                 try
                 {
-                    var timeoutTask = Task.Delay(timeout, cancellationTokenSource.Token);
+                    var timeoutTask = Task.Delay(timeout, timeoutCts.Token);
                     var finishedTask = await Task.WhenAny(timeoutTask, task).ConfigureAwait(false);
 
                     if (finishedTask == timeoutTask)
@@ -66,7 +70,7 @@ namespace MQTTnet.Core.Internal
                 }
                 finally
                 {
-                    cancellationTokenSource.Cancel();
+                    timeoutCts.Cancel();
                 }
             }
         }

Frameworks/MQTTnet.NetStandard/MQTTnet.Netstandard.csproj

@@ -1,19 +1,23 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard1.3;netstandard2.0;net452;net461;uap10.0</TargetFrameworks>
+    <TargetFrameworks Condition=" '$(OS)' == 'Windows_NT' ">netstandard1.3;netstandard2.0;net452;net461;uap10.0</TargetFrameworks>
+    <TargetFrameworks Condition=" '$(OS)' != 'Windows_NT' ">netstandard1.3;netstandard2.0</TargetFrameworks>
     <AssemblyName>MQTTnet</AssemblyName>
     <RootNamespace>MQTTnet</RootNamespace>
     <GeneratePackageOnBuild>False</GeneratePackageOnBuild>
     <DebugType>Full</DebugType>
-    <AssemblyVersion>2.5.3.0</AssemblyVersion>
+    <AssemblyVersion>0.0.0.0</AssemblyVersion>
-    <FileVersion>2.5.3.0</FileVersion>
+    <FileVersion>0.0.0.0</FileVersion>
     <Version>0.0.0.0</Version>
     <Company />
     <Product />
     <Description />
     <Authors />
     <PackageId />
+    <SignAssembly>true</SignAssembly>
+    <AssemblyOriginatorKeyFile>codeSigningKey.pfx</AssemblyOriginatorKeyFile>
+    <DelaySign>false</DelaySign>
   </PropertyGroup>
 
   <PropertyGroup Condition="'$(TargetFramework)' == 'uap10.0'">
@@ -26,16 +30,15 @@
     <TargetFrameworkVersion>v5.0</TargetFrameworkVersion>
     <DefineConstants>$(DefineConstants);WINDOWS_UWP</DefineConstants>
     <LanguageTargets>$(MSBuildExtensionsPath)\Microsoft\WindowsXaml\v$(VisualStudioVersion)\Microsoft.Windows.UI.Xaml.CSharp.targets</LanguageTargets>
-    
   </PropertyGroup>
 
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x86'" />
 
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" />
 
-  <ItemGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(TargetFramework)|$(Platform)'=='Release|netstandard1.3|AnyCPU'">
-    <ProjectReference Include="..\..\MQTTnet.Core\MQTTnet.Core.csproj" />
+    <DefineConstants>RELEASE;NETSTANDARD1_3</DefineConstants>
-  </ItemGroup>
+  </PropertyGroup>
 
   <ItemGroup Condition="'$(TargetFramework)'=='netstandard2.0'">
     <PackageReference Include="System.Net.Security" Version="4.3.2" />

Frameworks/MQTTnet.NetStandard/ManagedClient/IManagedMqttClient.cs

@@ -1,11 +1,11 @@
 using System;
 using System.Collections.Generic;
 using System.Threading.Tasks;
-using MQTTnet.Core.Client;
+using MQTTnet.Client;
 
-namespace MQTTnet.Core.ManagedClient
+namespace MQTTnet.ManagedClient
 {
-    public interface IManagedMqttClient : IApplicationMessageReceiver, IApplicationMessagePublisher
+    public interface IManagedMqttClient : IApplicationMessageReceiver, IApplicationMessagePublisher, IDisposable
     {
         bool IsConnected { get; }
 
@@ -16,6 +16,6 @@ namespace MQTTnet.Core.ManagedClient
         Task StopAsync();
 
         Task SubscribeAsync(IEnumerable<TopicFilter> topicFilters);
-        Task UnsubscribeAsync(IEnumerable<TopicFilter> topicFilters);
+        Task UnsubscribeAsync(IEnumerable<string> topics);
     }
 }

Frameworks/MQTTnet.NetStandard/ManagedClient/IManagedMqttClientOptions.cs

@@ -1,7 +1,7 @@
 using System;
-using MQTTnet.Core.Client;
+using MQTTnet.Client;
 
-namespace MQTTnet.Core.ManagedClient
+namespace MQTTnet.ManagedClient
 {
     public interface IManagedMqttClientOptions
     {

Frameworks/MQTTnet.NetStandard/ManagedClient/IManagedMqttClientStorage.cs

@@ -1,7 +1,7 @@
 using System.Collections.Generic;
 using System.Threading.Tasks;
 
-namespace MQTTnet.Core.ManagedClient
+namespace MQTTnet.ManagedClient
 {
     public interface IManagedMqttClientStorage
     {

Frameworks/MQTTnet.NetStandard/ManagedClient/ManagedMqttClient.cs

@@ -4,18 +4,18 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
-using MQTTnet.Core.Client;
+using MQTTnet.Client;
-using MQTTnet.Core.Diagnostics;
+using MQTTnet.Diagnostics;
-using MQTTnet.Core.Exceptions;
+using MQTTnet.Exceptions;
-using MQTTnet.Core.Protocol;
+using MQTTnet.Protocol;
 
-namespace MQTTnet.Core.ManagedClient
+namespace MQTTnet.ManagedClient
 {
     public class ManagedMqttClient : IManagedMqttClient
     {
-        private readonly ManagedMqttClientStorageManager _storageManager = new ManagedMqttClientStorageManager();
         private readonly BlockingCollection<MqttApplicationMessage> _messageQueue = new BlockingCollection<MqttApplicationMessage>();
-        private readonly HashSet<TopicFilter> _subscriptions = new HashSet<TopicFilter>();
+        private readonly Dictionary<string, MqttQualityOfServiceLevel> _subscriptions = new Dictionary<string, MqttQualityOfServiceLevel>();
+        private readonly SemaphoreSlim _subscriptionsSemaphore = new SemaphoreSlim(1, 1);
 
         private readonly IMqttClient _mqttClient;
         private readonly IMqttNetLogger _logger;
@@ -23,7 +23,9 @@ namespace MQTTnet.Core.ManagedClient
         private CancellationTokenSource _connectionCancellationToken;
         private CancellationTokenSource _publishingCancellationToken;
 
+        private ManagedMqttClientStorageManager _storageManager;
         private IManagedMqttClientOptions _options;
+
         private bool _subscriptionsNotPushed;
         
         public ManagedMqttClient(IMqttClient mqttClient, IMqttNetLogger logger)
@@ -55,15 +57,11 @@ namespace MQTTnet.Core.ManagedClient
             if (_connectionCancellationToken != null) throw new InvalidOperationException("The managed client is already started.");
 
             _options = options;
-            await _storageManager.SetStorageAsync(_options.Storage).ConfigureAwait(false);
+            
-
             if (_options.Storage != null)
             {
-                var loadedMessages = await _options.Storage.LoadQueuedMessagesAsync().ConfigureAwait(false);
+                _storageManager = new ManagedMqttClientStorageManager(_options.Storage);
-                foreach (var loadedMessage in loadedMessages)
+                await _storageManager.LoadQueuedMessagesAsync().ConfigureAwait(false);
-                {
-                    _messageQueue.Add(loadedMessage);    
-                }
             }
 
             _connectionCancellationToken = new CancellationTokenSource();
@@ -77,11 +75,8 @@ namespace MQTTnet.Core.ManagedClient
 
         public Task StopAsync()
         {
-            _connectionCancellationToken?.Cancel(false);
+            StopPublishing();
-            _connectionCancellationToken = null;
+            StopMaintainingConnection();
-
-            _publishingCancellationToken?.Cancel(false);
-            _publishingCancellationToken = null;
 
             while (_messageQueue.Any())
             {
@@ -90,50 +85,66 @@ namespace MQTTnet.Core.ManagedClient
 
             return Task.FromResult(0);
         }
-
+        
         public async Task PublishAsync(IEnumerable<MqttApplicationMessage> applicationMessages)
         {
             if (applicationMessages == null) throw new ArgumentNullException(nameof(applicationMessages));
 
             foreach (var applicationMessage in applicationMessages)
             {
-                await _storageManager.AddAsync(applicationMessage).ConfigureAwait(false);
+                if (_storageManager != null)
+                {
+                    await _storageManager.AddAsync(applicationMessage).ConfigureAwait(false);
+                }
+                
                 _messageQueue.Add(applicationMessage);
             }
         }
 
-        public Task SubscribeAsync(IEnumerable<TopicFilter> topicFilters)
+        public async Task SubscribeAsync(IEnumerable<TopicFilter> topicFilters)
         {
             if (topicFilters == null) throw new ArgumentNullException(nameof(topicFilters));
 
-            lock (_subscriptions)
+            await _subscriptionsSemaphore.WaitAsync().ConfigureAwait(false);
+            try
             {
                 foreach (var topicFilter in topicFilters)
                 {
-                    if (_subscriptions.Add(topicFilter))
+                    _subscriptions[topicFilter.Topic] = topicFilter.QualityOfServiceLevel;
-                    {
+                    _subscriptionsNotPushed = true;
-                        _subscriptionsNotPushed = true;
-                    }
                 }
             }
-
+            finally
-            return Task.FromResult(0);
+            {
+                _subscriptionsSemaphore.Release();
+            }
         }
 
-        public Task UnsubscribeAsync(IEnumerable<TopicFilter> topicFilters)
+        public async Task UnsubscribeAsync(IEnumerable<string> topics)
         {
-            lock (_subscriptions)
+            await _subscriptionsSemaphore.WaitAsync().ConfigureAwait(false);
+            try
             {
-                foreach (var topicFilter in topicFilters)
+                foreach (var topic in topics)
                 {
-                    if (_subscriptions.Remove(topicFilter))
+                    if (_subscriptions.Remove(topic))
                     {
                         _subscriptionsNotPushed = true;
                     }
                 }
             }
+            finally
+            {
+                _subscriptionsSemaphore.Release();
+            }
+        }
 
-            return Task.FromResult(0);
+        public void Dispose()
+        {
+            _messageQueue?.Dispose();
+            _subscriptionsSemaphore?.Dispose();
+            _connectionCancellationToken?.Dispose();
+            _publishingCancellationToken?.Dispose();
         }
 
         private async Task MaintainConnectionAsync(CancellationToken cancellationToken)
@@ -142,33 +153,48 @@ namespace MQTTnet.Core.ManagedClient
             {
                 while (!cancellationToken.IsCancellationRequested)
                 {
-                    var connectionState = await ReconnectIfRequiredAsync().ConfigureAwait(false);
+                    await TryMaintainConnectionAsync(cancellationToken);
-                    if (connectionState == ReconnectionResult.NotConnected)
+                }
-                    {
+            }
-                        _publishingCancellationToken?.Cancel(false);
+            catch (OperationCanceledException)
-                        _publishingCancellationToken = null;
+            {
+            }
+            catch (Exception exception)
+            {
+                _logger.Error<ManagedMqttClient>(exception, "Unhandled exception while maintaining connection.");
+            }
+            finally
+            {
+                await _mqttClient.DisconnectAsync().ConfigureAwait(false);
+                _logger.Info<ManagedMqttClient>("Stopped");
+            }
+        }
 
-                        await Task.Delay(_options.AutoReconnectDelay, cancellationToken).ConfigureAwait(false);
+        private async Task TryMaintainConnectionAsync(CancellationToken cancellationToken)
-                        continue;
+        {
-                    }
+            try
+            {
+                var connectionState = await ReconnectIfRequiredAsync().ConfigureAwait(false);
+                if (connectionState == ReconnectionResult.NotConnected)
+                {
+                    StopPublishing();
+                    await Task.Delay(_options.AutoReconnectDelay, cancellationToken).ConfigureAwait(false);
+                    return;
+                }
 
-                    if (connectionState == ReconnectionResult.Reconnected || _subscriptionsNotPushed)
+                if (connectionState == ReconnectionResult.Reconnected || _subscriptionsNotPushed)
-                    {
+                {
-                        await PushSubscriptionsAsync();
+                    await PushSubscriptionsAsync().ConfigureAwait(false);
 
-                        _publishingCancellationToken = new CancellationTokenSource();
+                    StartPublishing();
 
-#pragma warning disable CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
+                    
-                        Task.Run(async () => await PublishQueuedMessagesAsync(_publishingCancellationToken.Token), _publishingCancellationToken.Token).ConfigureAwait(false);
+                    return;
-#pragma warning restore CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
+                }
 
-                        continue;
+                if (connectionState == ReconnectionResult.StillConnected)
-                    }
+                {
-
+                    await Task.Delay(TimeSpan.FromSeconds(1), cancellationToken).ConfigureAwait(false);
-                    if (connectionState == ReconnectionResult.StillConnected)
-                    {
-                        await Task.Delay(TimeSpan.FromSeconds(1), _connectionCancellationToken.Token).ConfigureAwait(false);
-                    }
                 }
             }
             catch (OperationCanceledException)
@@ -182,13 +208,8 @@ namespace MQTTnet.Core.ManagedClient
             {
                 _logger.Error<ManagedMqttClient>(exception, "Unhandled exception while maintaining connection.");
             }
-            finally
-            {
-                await _mqttClient.DisconnectAsync().ConfigureAwait(false);
-                _logger.Info<ManagedMqttClient>("Stopped");
-            }
         }
-
+        
         private async Task PublishQueuedMessagesAsync(CancellationToken cancellationToken)
         {
             try
@@ -206,16 +227,19 @@ namespace MQTTnet.Core.ManagedClient
                         continue;
                     }
 
-                    await TryPublishQueuedMessageAsync(message).ConfigureAwait(false);
+                    await TryPublishQueuedMessageAsync(message).ConfigureAwait(false);                 
-                    await _storageManager.RemoveAsync(message).ConfigureAwait(false);
                 }
             }
             catch (OperationCanceledException)
             {
             }
+            catch (Exception exception)
+            {
+                _logger.Error<ManagedMqttClient>(exception, "Unhandled exception while publishing queued application messages.");
+            }
             finally
             {
-                _logger.Info<ManagedMqttClient>("Stopped publishing messages");
+                _logger.Trace<ManagedMqttClient>("Stopped publishing messages.");
             }
         }
 
@@ -224,6 +248,11 @@ namespace MQTTnet.Core.ManagedClient
             try
             {
                 await _mqttClient.PublishAsync(message).ConfigureAwait(false);
+
+                if (_storageManager != null)
+                {
+                    await _storageManager.RemoveAsync(message).ConfigureAwait(false);
+                }
             }
             catch (MqttCommunicationException exception)
             {
@@ -245,13 +274,18 @@ namespace MQTTnet.Core.ManagedClient
             _logger.Info<ManagedMqttClient>(nameof(ManagedMqttClient), "Synchronizing subscriptions");
 
             List<TopicFilter> subscriptions;
-            lock (_subscriptions)
+            await _subscriptionsSemaphore.WaitAsync().ConfigureAwait(false);
+            try
             {
-                subscriptions = _subscriptions.ToList();
+                subscriptions = _subscriptions.Select(i => new TopicFilter(i.Key, i.Value)).ToList();
                 _subscriptionsNotPushed = false;
             }
+            finally
+            {
+                _subscriptionsSemaphore.Release();
+            }
 
-            if (!_subscriptions.Any())
+            if (!subscriptions.Any())
             {
                 return;
             }
@@ -299,5 +333,35 @@ namespace MQTTnet.Core.ManagedClient
         {
             Connected?.Invoke(this, eventArgs);
         }
+
+        private void StartPublishing()
+        {
+            if (_publishingCancellationToken != null)
+            {
+                StopPublishing();
+            }
+
+            var cts = new CancellationTokenSource();
+
+            _publishingCancellationToken = cts;
+
+#pragma warning disable CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
+            Task.Run(async () => await PublishQueuedMessagesAsync(cts.Token).ConfigureAwait(false), cts.Token).ConfigureAwait(false);
+#pragma warning restore CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
+        }
+
+        private void StopPublishing()
+        {
+            _publishingCancellationToken?.Cancel(false);
+            _publishingCancellationToken?.Dispose();
+            _publishingCancellationToken = null;
+        }
+
+        private void StopMaintainingConnection()
+        {
+            _connectionCancellationToken?.Cancel(false);
+            _connectionCancellationToken?.Dispose();
+            _connectionCancellationToken = null;
+        }
     }
 }

Frameworks/MQTTnet.NetStandard/ManagedClient/ManagedMqttClientExtensions.cs

@@ -1,7 +1,8 @@
 using System;
 using System.Threading.Tasks;
+using MQTTnet.Protocol;
 
-namespace MQTTnet.Core.ManagedClient
+namespace MQTTnet.ManagedClient
 {
     public static class ManagedMqttClientExtensions
     {
@@ -12,7 +13,15 @@ namespace MQTTnet.Core.ManagedClient
             return managedClient.SubscribeAsync(topicFilters);
         }
 
-        public static Task UnsubscribeAsync(this IManagedMqttClient managedClient, params TopicFilter[] topicFilters)
+        public static Task SubscribeAsync(this IManagedMqttClient managedClient, string topic, MqttQualityOfServiceLevel qualityOfServiceLevel)
+        {
+            if (managedClient == null) throw new ArgumentNullException(nameof(managedClient));
+            if (topic == null) throw new ArgumentNullException(nameof(topic));
+
+            return managedClient.SubscribeAsync(new TopicFilterBuilder().WithTopic(topic).WithQualityOfServiceLevel(qualityOfServiceLevel).Build());
+        }
+
+        public static Task UnsubscribeAsync(this IManagedMqttClient managedClient, params string[] topicFilters)
         {
             if (managedClient == null) throw new ArgumentNullException(nameof(managedClient));
 

Frameworks/MQTTnet.NetStandard/ManagedClient/ManagedMqttClientOptions.cs

@@ -1,7 +1,7 @@
 using System;
-using MQTTnet.Core.Client;
+using MQTTnet.Client;
 
-namespace MQTTnet.Core.ManagedClient
+namespace MQTTnet.ManagedClient
 {
     public class ManagedMqttClientOptions : IManagedMqttClientOptions
     {

Frameworks/MQTTnet.NetStandard/ManagedClient/ManagedMqttClientOptionsBuilder.cs

@@ -1,7 +1,7 @@
 using System;
-using MQTTnet.Core.Client;
+using MQTTnet.Client;
 
-namespace MQTTnet.Core.ManagedClient
+namespace MQTTnet.ManagedClient
 {
     public class ManagedMqttClientOptionsBuilder
     {

Frameworks/MQTTnet.NetStandard/ManagedClient/ManagedMqttClientStorageManager.cs

@@ -1,25 +1,27 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.Threading;
 using System.Threading.Tasks;
 
-namespace MQTTnet.Core.ManagedClient
+namespace MQTTnet.ManagedClient
 {
     public class ManagedMqttClientStorageManager
     {
         private readonly List<MqttApplicationMessage> _applicationMessages = new List<MqttApplicationMessage>();
         private readonly SemaphoreSlim _semaphore = new SemaphoreSlim(1, 1);
-        private IManagedMqttClientStorage _storage;
+        private readonly IManagedMqttClientStorage _storage;
 
-        public async Task SetStorageAsync(IManagedMqttClientStorage storage)
+        public ManagedMqttClientStorageManager(IManagedMqttClientStorage storage)
         {
-            await _semaphore.WaitAsync().ConfigureAwait(false);
+            _storage = storage ?? throw new ArgumentNullException(nameof(storage));
-            try
+        }
+
+        public async Task LoadQueuedMessagesAsync()
+        {
+            var loadedMessages = await _storage.LoadQueuedMessagesAsync().ConfigureAwait(false);
+            foreach (var loadedMessage in loadedMessages)
             {
-                _storage = storage;
+                _applicationMessages.Add(loadedMessage);
-            }
-            finally
-            {
-                _semaphore.Release();
             }
         }
 
@@ -28,11 +30,6 @@ namespace MQTTnet.Core.ManagedClient
             await _semaphore.WaitAsync().ConfigureAwait(false);
             try
             {
-                if (_storage == null)
-                {
-                    return;
-                }
-
                 _applicationMessages.Add(applicationMessage);
                 await SaveAsync().ConfigureAwait(false);
             }
@@ -47,11 +44,6 @@ namespace MQTTnet.Core.ManagedClient
             await _semaphore.WaitAsync().ConfigureAwait(false);
             try
             {
-                if (_storage == null)
-                {
-                    return;
-                }
-
                 var index = _applicationMessages.IndexOf(applicationMessage);
                 if (index == -1)
                 {

Frameworks/MQTTnet.NetStandard/ManagedClient/ReconnectionResult.cs

@@ -1,4 +1,4 @@
-namespace MQTTnet.Core.ManagedClient
+namespace MQTTnet.ManagedClient
 {
     public enum ReconnectionResult
     {

Frameworks/MQTTnet.NetStandard/MqttApplicationMessage.cs

@@ -1,7 +1,7 @@
 using System;
-using MQTTnet.Core.Protocol;
+using MQTTnet.Protocol;
 
-namespace MQTTnet.Core
+namespace MQTTnet
 {
     public sealed class MqttApplicationMessage
     {

Frameworks/MQTTnet.NetStandard/MqttApplicationMessageBuilder.cs

@@ -2,10 +2,10 @@
 using System.IO;
 using System.Linq;
 using System.Text;
-using MQTTnet.Core.Exceptions;
+using MQTTnet.Exceptions;
-using MQTTnet.Core.Protocol;
+using MQTTnet.Protocol;
 
-namespace MQTTnet.Core
+namespace MQTTnet
 {
     public class MqttApplicationMessageBuilder
     {

Frameworks/MQTTnet.NetStandard/MqttApplicationMessageReceivedEventArgs.cs

@@ -1,6 +1,6 @@
 using System;
 
-namespace MQTTnet.Core
+namespace MQTTnet
 {
     public sealed class MqttApplicationMessageReceivedEventArgs : EventArgs
     {

Frameworks/MQTTnet.NetStandard/MqttFactory.cs

@@ -1,11 +1,11 @@
 using System;
 using System.Collections.Generic;
-using MQTTnet.Core.Adapter;
+using MQTTnet.Adapter;
-using MQTTnet.Core.Client;
+using MQTTnet.Client;
+using MQTTnet.Diagnostics;
 using MQTTnet.Implementations;
-using MQTTnet.Core.ManagedClient;
+using MQTTnet.ManagedClient;
-using MQTTnet.Core.Server;
+using MQTTnet.Server;
-using MQTTnet.Core.Diagnostics;
 
 namespace MQTTnet
 {

Frameworks/MQTTnet.NetStandard/Packets/IMqttPacketWithIdentifier.cs

@@ -1,4 +1,4 @@
-namespace MQTTnet.Core.Packets
+namespace MQTTnet.Packets
 {
     public interface IMqttPacketWithIdentifier
     {

Frameworks/MQTTnet.NetStandard/Packets/MqttBasePacket.cs

@@ -1,4 +1,4 @@
-namespace MQTTnet.Core.Packets
+namespace MQTTnet.Packets
 {
     public abstract class MqttBasePacket
     {

Frameworks/MQTTnet.NetStandard/Packets/MqttBasePublishPacket.cs

@@ -1,4 +1,4 @@
-namespace MQTTnet.Core.Packets
+namespace MQTTnet.Packets
 {
     public class MqttBasePublishPacket : MqttBasePacket, IMqttPacketWithIdentifier
     {

Frameworks/MQTTnet.NetStandard/Packets/MqttConnAckPacket.cs

@@ -1,6 +1,6 @@
-using MQTTnet.Core.Protocol;
+using MQTTnet.Protocol;
 
-namespace MQTTnet.Core.Packets
+namespace MQTTnet.Packets
 {
     public sealed class MqttConnAckPacket : MqttBasePacket
     {

Frameworks/MQTTnet.NetStandard/Packets/MqttConnectPacket.cs

@@ -1,6 +1,6 @@
-using MQTTnet.Core.Serializer;
+using MQTTnet.Serializer;
 
-namespace MQTTnet.Core.Packets
+namespace MQTTnet.Packets
 {
     public sealed class MqttConnectPacket : MqttBasePacket
     {

Frameworks/MQTTnet.NetStandard/Packets/MqttDisconnectPacket.cs

@@ -1,4 +1,4 @@
-namespace MQTTnet.Core.Packets
+namespace MQTTnet.Packets
 {
     public sealed class MqttDisconnectPacket : MqttBasePacket
     {

Frameworks/MQTTnet.NetStandard/Packets/MqttPacketExtensions.cs

@@ -1,6 +1,6 @@
 using System;
 
-namespace MQTTnet.Core.Packets
+namespace MQTTnet.Packets
 {
     public static class MqttPacketExtensions
     {

Frameworks/MQTTnet.NetStandard/Packets/MqttPacketHeader.cs

@@ -1,6 +1,6 @@
-using MQTTnet.Core.Protocol;
+using MQTTnet.Protocol;
 
-namespace MQTTnet.Core.Packets
+namespace MQTTnet.Packets
 {
     public class MqttPacketHeader
     {

Frameworks/MQTTnet.NetStandard/Packets/MqttPingReqPacket.cs

@@ -1,4 +1,4 @@
-namespace MQTTnet.Core.Packets
+namespace MQTTnet.Packets
 {
     public sealed class MqttPingReqPacket : MqttBasePacket
     {

Frameworks/MQTTnet.NetStandard/Packets/MqttPingRespPacket.cs

@@ -1,4 +1,4 @@
-namespace MQTTnet.Core.Packets
+namespace MQTTnet.Packets
 {
     public sealed class MqttPingRespPacket : MqttBasePacket
     {

Frameworks/MQTTnet.NetStandard/Packets/MqttPubAckPacket.cs

@@ -1,4 +1,4 @@
-namespace MQTTnet.Core.Packets
+namespace MQTTnet.Packets
 {
     public sealed class MqttPubAckPacket : MqttBasePublishPacket
     {

Frameworks/MQTTnet.NetStandard/Packets/MqttPubCompPacket.cs

@@ -1,4 +1,4 @@
-namespace MQTTnet.Core.Packets
+namespace MQTTnet.Packets
 {
     public sealed class MqttPubCompPacket : MqttBasePublishPacket
     {

Frameworks/MQTTnet.NetStandard/Packets/MqttPubRecPacket.cs

@@ -1,4 +1,4 @@
-namespace MQTTnet.Core.Packets
+namespace MQTTnet.Packets
 {
     public sealed class MqttPubRecPacket : MqttBasePublishPacket
     {

Frameworks/MQTTnet.NetStandard/Packets/MqttPubRelPacket.cs

@@ -1,4 +1,4 @@
-namespace MQTTnet.Core.Packets
+namespace MQTTnet.Packets
 {
     public sealed class MqttPubRelPacket : MqttBasePublishPacket
     {

Frameworks/MQTTnet.NetStandard/Packets/MqttPublishPacket.cs

@@ -1,6 +1,6 @@
-using MQTTnet.Core.Protocol;
+using MQTTnet.Protocol;
 
-namespace MQTTnet.Core.Packets
+namespace MQTTnet.Packets
 {
     public sealed class MqttPublishPacket : MqttBasePublishPacket
     {

Frameworks/MQTTnet.NetStandard/Packets/MqttSubAckPacket.cs

@@ -1,8 +1,8 @@
 using System.Collections.Generic;
 using System.Linq;
-using MQTTnet.Core.Protocol;
+using MQTTnet.Protocol;
 
-namespace MQTTnet.Core.Packets
+namespace MQTTnet.Packets
 {
     public sealed class MqttSubAckPacket : MqttBasePacket, IMqttPacketWithIdentifier
     {

Frameworks/MQTTnet.NetStandard/Packets/MqttSubscribePacket.cs

@@ -1,7 +1,7 @@
 using System.Collections.Generic;
 using System.Linq;
 
-namespace MQTTnet.Core.Packets
+namespace MQTTnet.Packets
 {
     public sealed class MqttSubscribePacket : MqttBasePacket, IMqttPacketWithIdentifier
     {

Frameworks/MQTTnet.NetStandard/Packets/MqttUnsubAckPacket.cs

@@ -1,4 +1,4 @@
-namespace MQTTnet.Core.Packets
+namespace MQTTnet.Packets
 {
     public sealed class MqttUnsubAckPacket : MqttBasePacket, IMqttPacketWithIdentifier
     {

Frameworks/MQTTnet.NetStandard/Packets/MqttUnsubscribe.cs

@@ -1,6 +1,6 @@
 using System.Collections.Generic;
 
-namespace MQTTnet.Core.Packets
+namespace MQTTnet.Packets
 {
     public sealed class MqttUnsubscribePacket : MqttBasePacket, IMqttPacketWithIdentifier
     {