Add Unit Tests

.github/workflows/ReleaseNotes.md

@@ -1,11 +1,4 @@
 * [Client] Fixed _PlatformNotSupportedException_ when using Blazor (#1755, thanks to @Nickztar).
-* [Client] Added hot reload of client certificates (#1781).
-* [Client] Added several new option builders and aligned usage (#1781, BREAKING CHANGE!).
-* [Client] Added support for _RemoteCertificateValidationCallback_ for .NET 4.5.2, 4.6.1 and 4.8 (#1806, thanks to @troky).
-* [Client] Fixed wrong logging of obsolete feature when connection was not successful (#1801, thanks to @ramonsmits).
-* [Client] Fixed _NullReferenceException_ when performing several actions when not connected (#1800, thanks to @ramonsmits).
-* [RpcClient] Added support for passing custom parameters to topic generation context (#1798, thanks to @Temppus).
 * [Server] Fixed _NullReferenceException_ in retained messages management (#1762, thanks to @logicaloud).
 * [Server] Exposed new option which allows disabling packet fragmentation (#1753).
 * [Server] Expired sessions will no longer be used when a client connects (#1756).
-* [Server] Fixed an issue in connection handling for ASP.NET connections (#1819, thanks to @CZEMacLeod).

.github/workflows/ci.yml

@@ -3,7 +3,7 @@ name: CI
 on: [push, pull_request]
 
 env:
-  VERSION: "4.3.0.${{github.run_number}}"
+  VERSION: "4.2.1.${{github.run_number}}"
 
 jobs:
   build:

Samples/Client/Client_Connection_Samples.cs

@@ -70,6 +70,32 @@ public static class Client_Connection_Samples
             await mqttClient.DisconnectAsync(mqttClientDisconnectOptions, CancellationToken.None);
         }
     }
+    
+    public static async Task Connect_With_Amazon_AWS()
+    {
+        /*
+         * This sample creates a simple MQTT client and connects to an Amazon Web Services broker.
+         *
+         * The broker requires special settings which are set here.
+         */
+
+        var mqttFactory = new MqttFactory();
+
+        using (var mqttClient = mqttFactory.CreateMqttClient())
+        {
+            var mqttClientOptions = new MqttClientOptionsBuilder()
+                .WithTcpServer("amazon.web.services.broker")
+                // Disabling packet fragmentation is very important!  
+                .WithoutPacketFragmentation()
+                .Build();
+            
+            await mqttClient.ConnectAsync(mqttClientOptions, CancellationToken.None);
+
+            Console.WriteLine("The MQTT client is connected.");
+
+            await mqttClient.DisconnectAsync();
+        }
+    }
 
     public static async Task Connect_Client_Timeout()
     {
@@ -135,15 +161,15 @@ public static class Client_Connection_Samples
         using (var mqttClient = mqttFactory.CreateMqttClient())
         {
             var mqttClientOptions = new MqttClientOptionsBuilder().WithTcpServer("mqtt.fluux.io")
-                .WithTlsOptions(
+                .WithTls(
                     o =>
                     {
                         // The used public broker sometimes has invalid certificates. This sample accepts all
                         // certificates. This should not be used in live environments.
-                        o.WithCertificateValidationHandler(_ => true);
+                        o.CertificateValidationHandler = _ => true;
 
                         // The default value is determined by the OS. Set manually to force version.
-                        o.WithSslProtocols(SslProtocols.Tls12);
+                        o.SslProtocol = SslProtocols.Tls12;
                     })
                 .Build();
 
@@ -170,7 +196,7 @@ public static class Client_Connection_Samples
 
         using (var mqttClient = mqttFactory.CreateMqttClient())
         {
-            var mqttClientOptions = new MqttClientOptionsBuilder().WithWebSocketServer(o => o.WithUri("broker.hivemq.com:8000/mqtt")).Build();
+            var mqttClientOptions = new MqttClientOptionsBuilder().WithWebSocketServer("broker.hivemq.com:8000/mqtt").Build();
 
             var response = await mqttClient.ConnectAsync(mqttClientOptions, CancellationToken.None);
 
@@ -192,7 +218,7 @@ public static class Client_Connection_Samples
 
         using (var mqttClient = mqttFactory.CreateMqttClient())
         {
-            var mqttClientOptions = new MqttClientOptionsBuilder().WithWebSocketServer(o => o.WithUri("broker.hivemq.com:8000/mqtt")).Build();
+            var mqttClientOptions = new MqttClientOptionsBuilder().WithWebSocketServer("broker.hivemq.com:8000/mqtt").Build();
 
             var response = await mqttClient.ConnectAsync(mqttClientOptions, CancellationToken.None);
 
@@ -215,11 +241,13 @@ public static class Client_Connection_Samples
         using (var mqttClient = mqttFactory.CreateMqttClient())
         {
             var mqttClientOptions = new MqttClientOptionsBuilder().WithTcpServer("test.mosquitto.org", 8883)
-                .WithTlsOptions(
-                    o => o.WithCertificateValidationHandler(
+                .WithTls(
+                    o =>
+                    {
                         // The used public broker sometimes has invalid certificates. This sample accepts all
                         // certificates. This should not be used in live environments.
-                        _ => true))
+                        o.CertificateValidationHandler = _ => true;
+                    })
                 .Build();
 
             // In MQTTv5 the response contains much more information.
@@ -234,31 +262,6 @@ public static class Client_Connection_Samples
         }
     }
 
-    public static async Task Connect_With_Amazon_AWS()
-    {
-        /*
-         * This sample creates a simple MQTT client and connects to an Amazon Web Services broker.
-         *
-         * The broker requires special settings which are set here.
-         */
-
-        var mqttFactory = new MqttFactory();
-
-        using (var mqttClient = mqttFactory.CreateMqttClient())
-        {
-            var mqttClientOptions = new MqttClientOptionsBuilder().WithTcpServer("amazon.web.services.broker")
-                // Disabling packet fragmentation is very important!  
-                .WithoutPacketFragmentation()
-                .Build();
-
-            await mqttClient.ConnectAsync(mqttClientOptions, CancellationToken.None);
-
-            Console.WriteLine("The MQTT client is connected.");
-
-            await mqttClient.DisconnectAsync();
-        }
-    }
-
     public static async Task Disconnect_Clean()
     {
         /*
@@ -314,19 +317,18 @@ public static class Client_Connection_Samples
         using (var mqttClient = mqttFactory.CreateMqttClient())
         {
             var mqttClientOptions = new MqttClientOptionsBuilder().WithTcpServer("mqtt.fluux.io", 8883)
-                .WithTlsOptions(
+                .WithTls(
                     o =>
                     {
-                        o.WithCertificateValidationHandler(
-                            eventArgs =>
-                            {
-                                eventArgs.Certificate.Subject.DumpToConsole();
-                                eventArgs.Certificate.GetExpirationDateString().DumpToConsole();
-                                eventArgs.Chain.ChainPolicy.RevocationMode.DumpToConsole();
-                                eventArgs.Chain.ChainStatus.DumpToConsole();
-                                eventArgs.SslPolicyErrors.DumpToConsole();
-                                return true;
-                            });
+                        o.CertificateValidationHandler = eventArgs =>
+                        {
+                            eventArgs.Certificate.Subject.DumpToConsole();
+                            eventArgs.Certificate.GetExpirationDateString().DumpToConsole();
+                            eventArgs.Chain.ChainPolicy.RevocationMode.DumpToConsole();
+                            eventArgs.Chain.ChainStatus.DumpToConsole();
+                            eventArgs.SslPolicyErrors.DumpToConsole();
+                            return true;
+                        };
                     })
                 .Build();
 
@@ -432,4 +434,4 @@ public static class Client_Connection_Samples
                 });
         }
     }
-}
+}

Samples/Client/Client_Subscribe_Samples.cs

@@ -5,8 +5,8 @@
 // ReSharper disable UnusedType.Global
 // ReSharper disable UnusedMember.Global
 // ReSharper disable InconsistentNaming
-// ReSharper disable UnusedMember.Local
 
+using MQTTnet;
 using MQTTnet.Client;
 using MQTTnet.Packets;
 using MQTTnet.Protocol;
@@ -177,60 +177,4 @@ public static class Client_Subscribe_Samples
             response.DumpToConsole();
         }
     }
-
-    static void ConcurrentProcessingDisableAutoAcknowledge(CancellationToken shutdownToken, IMqttClient mqttClient)
-    {
-        /*
-         * This sample shows how to achieve concurrent processing and not have message AutoAcknowledged
-         * This to have a proper QoS1 (at-least-once) experience for what at least MQTT specification can provide
-         */
-        mqttClient.ApplicationMessageReceivedAsync += async ea =>
-        {
-            ea.AutoAcknowledge = false;
-
-            async Task ProcessAsync()
-            {
-                // DO YOUR WORK HERE!
-                await Task.Delay(1000, shutdownToken);
-                await ea.AcknowledgeAsync(shutdownToken);
-                // WARNING: If process failures are not transient the message will be retried on every restart of the client
-                //          A failed message will not be dispatched again to the client as MQTT does not have a NACK packet to let
-                //          the broker know processing failed
-                //
-                // Optionally: Use a framework like Polly to create a retry policy: https://github.com/App-vNext/Polly#retry
-            }
-
-            _ = Task.Run(ProcessAsync, shutdownToken);
-        };
-    }
-
-    static void ConcurrentProcessingWithLimit(CancellationToken shutdownToken, IMqttClient mqttClient)
-    {
-        /*
-         * This sample shows how to achieve concurrent processing, with:
-         * - a maximum concurrency limit based on Environment.ProcessorCount
-         */
-
-        var concurrent = new SemaphoreSlim(Environment.ProcessorCount);
-
-        mqttClient.ApplicationMessageReceivedAsync += async ea =>
-        {
-            await concurrent.WaitAsync(shutdownToken).ConfigureAwait(false);
-
-            async Task ProcessAsync()
-            {
-                try
-                {
-                    // DO YOUR WORK HERE!
-                    await Task.Delay(1000, shutdownToken);
-                }
-                finally
-                {
-                    concurrent.Release();
-                }
-            }
-
-            _ = Task.Run(ProcessAsync, shutdownToken);
-        };
-    }
-}
+}

Source/MQTTnet.AspnetCore/MqttConnectionContext.cs

@@ -33,11 +33,8 @@ namespace MQTTnet.AspNetCore
             PacketFormatterAdapter = packetFormatterAdapter ?? throw new ArgumentNullException(nameof(packetFormatterAdapter));
             _connection = connection ?? throw new ArgumentNullException(nameof(connection));
 
-            if (!(_connection is TcpConnection tcp) || tcp.IsConnected)
-            {
-                _input = connection.Transport.Input;
-                _output = connection.Transport.Output;
-            }
+            _input = connection.Transport.Input;
+            _output = connection.Transport.Output;
         }
 
         public long BytesReceived { get; private set; }

Source/MQTTnet.Extensions.Rpc/IMqttRpcClient.cs

@@ -1,5 +1,4 @@
 using System;
-using System.Collections.Generic;
 using System.Threading;
 using System.Threading.Tasks;
 using MQTTnet.Protocol;
@@ -8,8 +7,8 @@ namespace MQTTnet.Extensions.Rpc
 {
     public interface IMqttRpcClient : IDisposable
     {
-        Task<byte[]> ExecuteAsync(TimeSpan timeout, string methodName, byte[] payload, MqttQualityOfServiceLevel qualityOfServiceLevel, IDictionary<string,object> parameters = null);
+        Task<byte[]> ExecuteAsync(TimeSpan timeout, string methodName, byte[] payload, MqttQualityOfServiceLevel qualityOfServiceLevel);
         
-        Task<byte[]> ExecuteAsync(string methodName, byte[] payload, MqttQualityOfServiceLevel qualityOfServiceLevel, IDictionary<string, object> parameters = null, CancellationToken cancellationToken = default);
+        Task<byte[]> ExecuteAsync(string methodName, byte[] payload, MqttQualityOfServiceLevel qualityOfServiceLevel, CancellationToken cancellationToken = default);
     }
 }

Source/MQTTnet.Extensions.Rpc/MqttRpcClient.cs

@@ -4,7 +4,6 @@
 
 using System;
 using System.Collections.Concurrent;
-using System.Collections.Generic;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
@@ -43,13 +42,13 @@ namespace MQTTnet.Extensions.Rpc
             _waitingCalls.Clear();
         }
 
-        public async Task<byte[]> ExecuteAsync(TimeSpan timeout, string methodName, byte[] payload, MqttQualityOfServiceLevel qualityOfServiceLevel, IDictionary<string, object> parameters = null)
+        public async Task<byte[]> ExecuteAsync(TimeSpan timeout, string methodName, byte[] payload, MqttQualityOfServiceLevel qualityOfServiceLevel)
         {
             using (var timeoutToken = new CancellationTokenSource(timeout))
             {
                 try
                 {
-                    return await ExecuteAsync(methodName, payload, qualityOfServiceLevel, parameters, timeoutToken.Token).ConfigureAwait(false);
+                    return await ExecuteAsync(methodName, payload, qualityOfServiceLevel, timeoutToken.Token).ConfigureAwait(false);
                 }
                 catch (OperationCanceledException exception)
                 {
@@ -63,14 +62,19 @@ namespace MQTTnet.Extensions.Rpc
             }
         }
 
-        public async Task<byte[]> ExecuteAsync(string methodName, byte[] payload, MqttQualityOfServiceLevel qualityOfServiceLevel, IDictionary<string, object> parameters = null, CancellationToken cancellationToken = default)
+        public async Task<byte[]> ExecuteAsync(string methodName, byte[] payload, MqttQualityOfServiceLevel qualityOfServiceLevel, CancellationToken cancellationToken = default)
         {
             if (methodName == null)
             {
                 throw new ArgumentNullException(nameof(methodName));
             }
 
-            var context = new TopicGenerationContext(_mqttClient, _options, methodName, parameters, qualityOfServiceLevel);
+            if (!_mqttClient.IsConnected)
+            {
+                throw new MqttClientDisconnectedException(null);
+            }
+
+            var context = new TopicGenerationContext(_mqttClient, _options, methodName, qualityOfServiceLevel);
             var topicNames = _options.TopicGenerationStrategy.CreateRpcTopics(context);
 
             var requestTopic = topicNames.RequestTopic;

Source/MQTTnet.Extensions.Rpc/MqttRpcClientExtensions.cs

@@ -3,7 +3,6 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
-using System.Collections.Generic;
 using System.Text;
 using System.Threading.Tasks;
 using MQTTnet.Protocol;
@@ -12,13 +11,13 @@ namespace MQTTnet.Extensions.Rpc
 {
     public static class MqttRpcClientExtensions
     {
-        public static Task<byte[]> ExecuteAsync(this IMqttRpcClient client, TimeSpan timeout, string methodName, string payload, MqttQualityOfServiceLevel qualityOfServiceLevel, IDictionary<string,object> parameters = null)
+        public static Task<byte[]> ExecuteAsync(this IMqttRpcClient client, TimeSpan timeout, string methodName, string payload, MqttQualityOfServiceLevel qualityOfServiceLevel)
         {
             if (client == null) throw new ArgumentNullException(nameof(client));
 
             var buffer = Encoding.UTF8.GetBytes(payload ?? string.Empty);
 
-            return client.ExecuteAsync(timeout, methodName, buffer, qualityOfServiceLevel, parameters);
+            return client.ExecuteAsync(timeout, methodName, buffer, qualityOfServiceLevel);
         }
     }
 }

Source/MQTTnet.Extensions.Rpc/Options/TopicGeneration/TopicGenerationContext.cs

@@ -3,7 +3,6 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
-using System.Collections.Generic;
 using MQTTnet.Client;
 using MQTTnet.Protocol;
 
@@ -11,11 +10,9 @@ namespace MQTTnet.Extensions.Rpc
 {
     public sealed class TopicGenerationContext
     {
-        public TopicGenerationContext(IMqttClient mqttClient, MqttRpcClientOptions options, string methodName,
-            IDictionary<string, object> parameters, MqttQualityOfServiceLevel qualityOfServiceLevel)
+        public TopicGenerationContext(IMqttClient mqttClient, MqttRpcClientOptions options, string methodName, MqttQualityOfServiceLevel qualityOfServiceLevel)
         {
             MethodName = methodName ?? throw new ArgumentNullException(nameof(methodName));
-            Parameters = parameters;
             QualityOfServiceLevel = qualityOfServiceLevel;
             MqttClient = mqttClient ?? throw new ArgumentNullException(nameof(mqttClient));
             Options = options ?? throw new ArgumentNullException(nameof(options));
@@ -23,8 +20,6 @@ namespace MQTTnet.Extensions.Rpc
 
         public string MethodName { get; }
 
-        public IDictionary<string, object> Parameters { get; }
-
         public IMqttClient MqttClient { get; }
 
         public MqttRpcClientOptions Options { get; }

Source/MQTTnet.Extensions.WebSocket4Net/WebSocket4NetMqttChannel.cs

@@ -92,7 +92,18 @@ namespace MQTTnet.Extensions.WebSocket4Net
             var webSocketVersion = WebSocketVersion.None;
             var receiveBufferSize = 0;
 
-            var certificates = _webSocketOptions.TlsOptions?.ClientCertificatesProvider?.GetCertificates();
+            var certificates = new X509CertificateCollection();
+            if (_webSocketOptions.TlsOptions?.Certificates != null)
+            {
+                foreach (var certificate in _webSocketOptions.TlsOptions.Certificates)
+                {
+#if WINDOWS_UWP
+                    certificates.Add(new X509Certificate(certificate));
+#else
+                    certificates.Add(certificate);
+#endif
+                }
+            }
 
             _webSocket = new WebSocket(uri, subProtocol, cookies, customHeaders, userAgent, origin, webSocketVersion, proxy, sslProtocols, receiveBufferSize)
             {

Source/MQTTnet.TestApp/PublicBrokerTest.cs

@@ -20,7 +20,7 @@ namespace MQTTnet.TestApp
         {
 #if NET5_0_OR_GREATER
             // TLS13 is only available in Net5.0
-            var unsafeTls13 = new MqttClientTlsOptions
+            var unsafeTls13 = new MqttClientOptionsBuilderTlsParameters
             {
                 UseTls = true,
                 SslProtocol = SslProtocols.Tls13,
@@ -29,7 +29,7 @@ namespace MQTTnet.TestApp
             };
 #endif
             // Also defining TLS12 for servers that don't seem no to support TLS13.
-            var unsafeTls12 = new MqttClientTlsOptions
+            var unsafeTls12 = new MqttClientOptionsBuilderTlsParameters
             {
                 UseTls = true,
                 SslProtocol = SslProtocols.Tls12,
@@ -44,16 +44,16 @@ namespace MQTTnet.TestApp
 
             await ExecuteTestAsync(
                 "mqtt.eclipseprojects.io WS",
-                new MqttClientOptionsBuilder().WithWebSocketServer(o => o.WithUri("mqtt.eclipseprojects.io:80/mqtt")).WithProtocolVersion(MqttProtocolVersion.V311).Build());
+                new MqttClientOptionsBuilder().WithWebSocketServer("mqtt.eclipseprojects.io:80/mqtt").WithProtocolVersion(MqttProtocolVersion.V311).Build());
 
 #if NET5_0_OR_GREATER
             await ExecuteTestAsync("mqtt.eclipseprojects.io WS TLS13",
-                new MqttClientOptionsBuilder().WithWebSocketServer(o => o.WithUri("mqtt.eclipseprojects.io:443/mqtt"))
-                    .WithProtocolVersion(MqttProtocolVersion.V311).WithTlsOptions(unsafeTls13).Build());
+                new MqttClientOptionsBuilder().WithWebSocketServer("mqtt.eclipseprojects.io:443/mqtt")
+                    .WithProtocolVersion(MqttProtocolVersion.V311).WithTls(unsafeTls13).Build());
             
             await ExecuteTestAsync("mqtt.eclipseprojects.io WS TLS13 (WebSocket4Net)",
-                new MqttClientOptionsBuilder().WithWebSocketServer(o => o.WithUri("mqtt.eclipseprojects.io:443/mqtt"))
-                    .WithProtocolVersion(MqttProtocolVersion.V311).WithTlsOptions(unsafeTls13).Build(),
+                new MqttClientOptionsBuilder().WithWebSocketServer("mqtt.eclipseprojects.io:443/mqtt")
+                    .WithProtocolVersion(MqttProtocolVersion.V311).WithTls(unsafeTls13).Build(),
                     true);
 #endif
 
@@ -68,12 +68,12 @@ namespace MQTTnet.TestApp
 
             await ExecuteTestAsync(
                 "test.mosquitto.org TCP TLS12",
-                new MqttClientOptionsBuilder().WithTcpServer("test.mosquitto.org", 8883).WithProtocolVersion(MqttProtocolVersion.V311).WithTlsOptions(unsafeTls12).Build());
+                new MqttClientOptionsBuilder().WithTcpServer("test.mosquitto.org", 8883).WithProtocolVersion(MqttProtocolVersion.V311).WithTls(unsafeTls12).Build());
 
 #if NET5_0_OR_GREATER
             await ExecuteTestAsync("test.mosquitto.org TCP TLS13",
                 new MqttClientOptionsBuilder().WithTcpServer("test.mosquitto.org", 8883)
-                    .WithProtocolVersion(MqttProtocolVersion.V311).WithTlsOptions(unsafeTls13).Build());
+                    .WithProtocolVersion(MqttProtocolVersion.V311).WithTls(unsafeTls13).Build());
 #endif
 
             await ExecuteTestAsync(
@@ -81,21 +81,21 @@ namespace MQTTnet.TestApp
                 new MqttClientOptionsBuilder().WithTcpServer("test.mosquitto.org", 8885)
                     .WithCredentials("rw", "readwrite")
                     .WithProtocolVersion(MqttProtocolVersion.V311)
-                    .WithTlsOptions(unsafeTls12)
+                    .WithTls(unsafeTls12)
                     .Build());
 
             await ExecuteTestAsync(
                 "test.mosquitto.org WS",
-                new MqttClientOptionsBuilder().WithWebSocketServer(o => o.WithUri("test.mosquitto.org:8080/mqtt")).WithProtocolVersion(MqttProtocolVersion.V311).Build());
+                new MqttClientOptionsBuilder().WithWebSocketServer("test.mosquitto.org:8080/mqtt").WithProtocolVersion(MqttProtocolVersion.V311).Build());
 
             await ExecuteTestAsync(
                 "test.mosquitto.org WS (WebSocket4Net)",
-                new MqttClientOptionsBuilder().WithWebSocketServer(o => o.WithUri("test.mosquitto.org:8080/mqtt")).WithProtocolVersion(MqttProtocolVersion.V311).Build(),
+                new MqttClientOptionsBuilder().WithWebSocketServer("test.mosquitto.org:8080/mqtt").WithProtocolVersion(MqttProtocolVersion.V311).Build(),
                 true);
 
             await ExecuteTestAsync(
                 "test.mosquitto.org WS TLS12",
-                new MqttClientOptionsBuilder().WithWebSocketServer(o => o.WithUri("test.mosquitto.org:8081/mqtt")).WithProtocolVersion(MqttProtocolVersion.V311).WithTlsOptions(unsafeTls12).Build());
+                new MqttClientOptionsBuilder().WithWebSocketServer("test.mosquitto.org:8081/mqtt").WithProtocolVersion(MqttProtocolVersion.V311).WithTls(unsafeTls12).Build());
 
             // await ExecuteTestAsync(
             //     "test.mosquitto.org WS TLS12 (WebSocket4Net)",
@@ -109,30 +109,30 @@ namespace MQTTnet.TestApp
 
             await ExecuteTestAsync(
                 "broker.emqx.io TCP TLS12",
-                new MqttClientOptionsBuilder().WithTcpServer("broker.emqx.io", 8883).WithProtocolVersion(MqttProtocolVersion.V311).WithTlsOptions(unsafeTls12).Build());
+                new MqttClientOptionsBuilder().WithTcpServer("broker.emqx.io", 8883).WithProtocolVersion(MqttProtocolVersion.V311).WithTls(unsafeTls12).Build());
 
 #if NET5_0_OR_GREATER
             await ExecuteTestAsync("broker.emqx.io TCP TLS13",
                 new MqttClientOptionsBuilder().WithTcpServer("broker.emqx.io", 8883)
-                    .WithProtocolVersion(MqttProtocolVersion.V311).WithTlsOptions(unsafeTls13).Build());
+                    .WithProtocolVersion(MqttProtocolVersion.V311).WithTls(unsafeTls13).Build());
 #endif
 
             await ExecuteTestAsync(
                 "broker.emqx.io WS",
-                new MqttClientOptionsBuilder().WithWebSocketServer(o => o.WithUri("broker.emqx.io:8083/mqtt")).WithProtocolVersion(MqttProtocolVersion.V311).Build());
+                new MqttClientOptionsBuilder().WithWebSocketServer("broker.emqx.io:8083/mqtt").WithProtocolVersion(MqttProtocolVersion.V311).Build());
 
             await ExecuteTestAsync(
                 "broker.emqx.io WS (WebSocket4Net)",
-                new MqttClientOptionsBuilder().WithWebSocketServer(o => o.WithUri("broker.emqx.io:8084/mqtt")).WithProtocolVersion(MqttProtocolVersion.V311).Build(),
+                new MqttClientOptionsBuilder().WithWebSocketServer("broker.emqx.io:8084/mqtt").WithProtocolVersion(MqttProtocolVersion.V311).Build(),
                 true);
 
             await ExecuteTestAsync(
                 "broker.emqx.io WS TLS12",
-                new MqttClientOptionsBuilder().WithWebSocketServer(o => o.WithUri("broker.emqx.io:8084/mqtt")).WithProtocolVersion(MqttProtocolVersion.V311).WithTlsOptions(unsafeTls12).Build());
+                new MqttClientOptionsBuilder().WithWebSocketServer("broker.emqx.io:8084/mqtt").WithProtocolVersion(MqttProtocolVersion.V311).WithTls(unsafeTls12).Build());
 
             await ExecuteTestAsync(
                 "broker.emqx.io WS TLS12 (WebSocket4Net)",
-                new MqttClientOptionsBuilder().WithWebSocketServer(o => o.WithUri("broker.emqx.io:8084/mqtt")).WithProtocolVersion(MqttProtocolVersion.V311).WithTlsOptions(unsafeTls12).Build(),
+                new MqttClientOptionsBuilder().WithWebSocketServer("broker.emqx.io:8084/mqtt").WithProtocolVersion(MqttProtocolVersion.V311).WithTls(unsafeTls12).Build(),
                 true);
 
             // broker.hivemq.com
@@ -142,11 +142,11 @@ namespace MQTTnet.TestApp
 
             await ExecuteTestAsync(
                 "broker.hivemq.com WS",
-                new MqttClientOptionsBuilder().WithWebSocketServer(o => o.WithUri("broker.hivemq.com:8000/mqtt")).WithProtocolVersion(MqttProtocolVersion.V311).Build());
+                new MqttClientOptionsBuilder().WithWebSocketServer("broker.hivemq.com:8000/mqtt").WithProtocolVersion(MqttProtocolVersion.V311).Build());
 
             await ExecuteTestAsync(
                 "broker.hivemq.com WS (WebSocket4Net)",
-                new MqttClientOptionsBuilder().WithWebSocketServer(o => o.WithUri("broker.hivemq.com:8000/mqtt")).WithProtocolVersion(MqttProtocolVersion.V311).Build(),
+                new MqttClientOptionsBuilder().WithWebSocketServer("broker.hivemq.com:8000/mqtt").WithProtocolVersion(MqttProtocolVersion.V311).Build(),
                 true);
 
             // mqtt.swifitch.cz: Does not seem to operate any more

Source/MQTTnet.Tests/Clients/ManagedMqttClient/ManagedMqttClient_Tests.cs

@@ -421,7 +421,7 @@ namespace MQTTnet.Tests.Clients.ManagedMqttClient
                 var receivingClient = await CreateManagedClientAsync(testEnvironment, null, connectionCheckInterval);
                 var sendingClient = await testEnvironment.ConnectClient();
 
-                await sendingClient.PublishAsync(new MqttApplicationMessage { Topic = "topic", PayloadSegment = new ArraySegment<byte>( new byte[] { 1 }), Retain = true });
+                await sendingClient.PublishAsync(new MqttApplicationMessage { Topic = "topic", Payload = new byte[] { 1 }, Retain = true });
 
                 var subscribeTime = DateTime.UtcNow;
 
@@ -454,7 +454,7 @@ namespace MQTTnet.Tests.Clients.ManagedMqttClient
                 //wait a bit for the subscription to become established
                 await Task.Delay(500);
 
-                await sendingClient.PublishAsync(new MqttApplicationMessage { Topic = "topic", PayloadSegment = new ArraySegment<byte>(new byte[] { 1 }), Retain = true });
+                await sendingClient.PublishAsync(new MqttApplicationMessage { Topic = "topic", Payload = new byte[] { 1 }, Retain = true });
 
                 var messages = await SetupReceivingOfMessages(managedClient, 1);
 

Source/MQTTnet.Tests/Clients/MqttClient/MqttClient_Connection_Tests.cs

@@ -9,6 +9,7 @@ using System.Threading.Tasks;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using MQTTnet.Client;
 using MQTTnet.Exceptions;
+using MQTTnet.Extensions.Rpc;
 using MQTTnet.Formatter;
 using MQTTnet.Internal;
 using MQTTnet.Packets;
@@ -20,6 +21,38 @@ namespace MQTTnet.Tests.Clients.MqttClient
     [TestClass]
     public sealed class MqttClient_Connection_Tests : BaseTestClass
     {
+        [TestMethod]
+        public async Task Connect_Disconnect_Connect()
+        {
+            using (var testEnvironment = CreateTestEnvironment())
+            {
+                await testEnvironment.StartServer();
+
+                var clientOptions = testEnvironment.CreateDefaultClientOptions();
+                var client = testEnvironment.CreateClient();
+
+                await client.ConnectAsync(clientOptions);
+                await client.DisconnectAsync();
+                await client.ConnectAsync(clientOptions);
+            }
+        }
+
+        [TestMethod]
+        [ExpectedException(typeof(InvalidOperationException))]
+        public async Task Connect_Multiple_Times_Should_Fail()
+        {
+            using (var testEnvironment = CreateTestEnvironment())
+            {
+                await testEnvironment.StartServer();
+
+                var clientOptions = testEnvironment.CreateDefaultClientOptions();
+                var client = testEnvironment.CreateClient();
+
+                await client.ConnectAsync(clientOptions);
+                await client.ConnectAsync(clientOptions);
+            }
+        }
+
         [TestMethod]
         [ExpectedException(typeof(MqttCommunicationException))]
         public async Task Connect_To_Invalid_Server_Port_Not_Opened()
@@ -198,25 +231,15 @@ namespace MQTTnet.Tests.Clients.MqttClient
         }
 
         [TestMethod]
-        public async Task Throw_Proper_Exception_When_Not_Connected()
+        [ExpectedException(typeof(MqttClientDisconnectedException))]
+        public async Task Rpc_Client_Not_Connected()
         {
-            try
+            var factory = new MqttFactory();
+            using (var client = factory.CreateMqttClient())
             {
-                var mqttFactory = new MqttFactory();
-                using (var mqttClient = mqttFactory.CreateMqttClient())
-                {
-                    await mqttClient.SubscribeAsync("test", MqttQualityOfServiceLevel.AtLeastOnce);
-                }
+                var rpcClient = factory.CreateMqttRpcClient(client);
+                await rpcClient.ExecuteAsync("aaa", new byte[] { 1, 2, 3 }, MqttQualityOfServiceLevel.AtLeastOnce);
             }
-            catch (MqttCommunicationException exception)
-            {
-                if (exception.Message == "The client is not connected.")
-                {
-                    return;
-                }
-            }
-
-            Assert.Fail();
         }
     }
 }

Source/MQTTnet.Tests/Clients/MqttClient/MqttClient_Publish_Tests.cs

@@ -0,0 +1,59 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using MQTTnet.Client;
+using MQTTnet.Protocol;
+using MQTTnet.Server;
+
+namespace MQTTnet.Tests.Clients.MqttClient
+{
+    [TestClass]
+    public sealed class MqttClient_Publish_Tests : BaseTestClass
+    {
+        [TestMethod]
+        public async Task Acknowledge_After_Disconnect_Should_Fail()
+        {
+            using (var testEnvironment = CreateTestEnvironment())
+            {
+                var server = await testEnvironment.StartServer();
+
+                var client = await testEnvironment.ConnectClient();
+                await client.SubscribeAsync("TEST", MqttQualityOfServiceLevel.AtLeastOnce);
+
+                var flag = false;
+                
+                client.ApplicationMessageReceivedAsync += async args =>
+                {
+                    try
+                    {
+                        args.AutoAcknowledge = false;
+                        
+                        await client.DisconnectAsync();
+                        await args.AcknowledgeAsync();
+
+                        flag = true;
+                    }
+                    catch (Exception exception)
+                    {
+                        
+                    }
+                };
+
+                await server.InjectApplicationMessageAsync(
+                    new MqttApplicationMessage
+                    {
+                        Topic = "TEST"
+                    });
+
+                SpinWait.SpinUntil(() => flag, TimeSpan.FromSeconds(10));
+                
+                Assert.IsTrue(flag);
+            }
+        }
+    }
+}

Source/MQTTnet.Tests/Clients/MqttClient/MqttClient_Tests.cs

@@ -69,38 +69,8 @@ namespace MQTTnet.Tests.Clients.MqttClient
                 Assert.IsTrue(success);
             }
         }
+       
 
-        [TestMethod]
-        public async Task Connect_Disconnect_Connect()
-        {
-            using (var testEnvironment = CreateTestEnvironment())
-            {
-                await testEnvironment.StartServer();
-
-                var clientOptions = testEnvironment.CreateDefaultClientOptions();
-                var client = testEnvironment.CreateClient();
-
-                await client.ConnectAsync(clientOptions);
-                await client.DisconnectAsync();
-                await client.ConnectAsync(clientOptions);
-            }
-        }
-        
-        [TestMethod]
-        [ExpectedException(typeof(InvalidOperationException))]
-        public async Task Connect_Multiple_Times_Should_Fail()
-        {
-            using (var testEnvironment = CreateTestEnvironment())
-            {
-                await testEnvironment.StartServer();
-
-                var clientOptions = testEnvironment.CreateDefaultClientOptions();
-                var client = testEnvironment.CreateClient();
-
-                await client.ConnectAsync(clientOptions);
-                await client.ConnectAsync(clientOptions);
-            }
-        }
 
         [TestMethod]
         public async Task Disconnect_Event_Contains_Exception()
@@ -296,7 +266,7 @@ namespace MQTTnet.Tests.Clients.MqttClient
 
                 Assert.IsNotNull(receivedMessage);
                 Assert.AreEqual("A", receivedMessage.Topic);
-                Assert.AreEqual(null, receivedMessage.PayloadSegment.Array);
+                Assert.AreEqual(null, receivedMessage.Payload);
             }
         }
 
@@ -507,7 +477,7 @@ namespace MQTTnet.Tests.Clients.MqttClient
 
                 client2.ApplicationMessageReceivedAsync += e =>
                 {
-                    client2TopicResults.Add(Encoding.UTF8.GetString(e.ApplicationMessage.PayloadSegment.ToArray()));
+                    client2TopicResults.Add(Encoding.UTF8.GetString(e.ApplicationMessage.Payload));
                     return CompletedTask.Instance;
                 };
 

Source/MQTTnet.Tests/Clients/MqttClientOptionsBuilder_Tests.cs

@@ -10,7 +10,7 @@ using MQTTnet.Client;
 namespace MQTTnet.Tests.Clients
 {
     [TestClass]
-    public class MqttClientOptionsBuilder_Tests
+    public sealed class MqttClientOptionsBuilder_Tests
     {
         [TestMethod]
         public void WithConnectionUri_Credential_Test()

Source/MQTTnet.Tests/Extensions/Rpc_Tests.cs

@@ -3,7 +3,6 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
-using System.Collections.Generic;
 using System.Text;
 using System.Threading.Tasks;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
@@ -46,34 +45,6 @@ namespace MQTTnet.Tests.Extensions
             }
         }
 
-        [TestMethod]
-        public async Task Execute_Success_Parameters_Propagated_Correctly()
-        {
-            var paramValue = "123";
-            var parameters = new Dictionary<string, object>
-            {
-                { TestParametersTopicGenerationStrategy.ExpectedParamName, "123" },
-            };
-
-            using (var testEnvironment = CreateTestEnvironment())
-            {
-                await testEnvironment.StartServer();
-
-                var responseSender = await testEnvironment.ConnectClient(new MqttClientOptionsBuilder());
-                await responseSender.SubscribeAsync($"MQTTnet.RPC/+/ping/{paramValue}");
-
-                responseSender.ApplicationMessageReceivedAsync += e => responseSender.PublishStringAsync(e.ApplicationMessage.Topic + "/response", "pong");
-
-                using (var rpcClient = await testEnvironment.ConnectRpcClient(new MqttRpcClientOptionsBuilder()
-                           .WithTopicGenerationStrategy(new TestParametersTopicGenerationStrategy()).Build()))
-                {
-                    var response = await rpcClient.ExecuteAsync(TimeSpan.FromSeconds(5), "ping", "", MqttQualityOfServiceLevel.AtMostOnce, parameters);
-
-                    Assert.AreEqual("pong", Encoding.UTF8.GetString(response));
-                }
-            }
-        }
-
         [TestMethod]
         public Task Execute_Success_With_QoS_0()
         {
@@ -251,32 +222,5 @@ namespace MQTTnet.Tests.Extensions
                 };
             }
         }
-
-        class TestParametersTopicGenerationStrategy : IMqttRpcClientTopicGenerationStrategy
-        {
-            internal const string ExpectedParamName = "test_param_name";
-
-            public MqttRpcTopicPair CreateRpcTopics(TopicGenerationContext context)
-            {
-                if (context.Parameters == null)
-                {
-                    throw new InvalidOperationException("Parameters dictionary expected to be not null");
-                }
-
-                if (!context.Parameters.TryGetValue(ExpectedParamName, out var paramValue))
-                {
-                    throw new InvalidOperationException($"Parameter with name {ExpectedParamName} not present");
-                }
-
-                var requestTopic = $"MQTTnet.RPC/{Guid.NewGuid():N}/{context.MethodName}/{paramValue}";
-                var responseTopic = requestTopic + "/response";
-
-                return new MqttRpcTopicPair
-                {
-                    RequestTopic = requestTopic,
-                    ResponseTopic = responseTopic
-                };
-            }
-        }
     }
 }

Source/MQTTnet.Tests/Extensions/WebSocket4Net_Tests.cs

@@ -23,7 +23,7 @@ namespace MQTTnet.Tests.Extensions
 
             using (var client = factory.CreateMqttClient())
             {
-                var options = new MqttClientOptionsBuilder().WithWebSocketServer(o => o.WithUri("ws://a.b/mqtt")).WithTimeout(TimeSpan.FromSeconds(2)).Build();
+                var options = new MqttClientOptionsBuilder().WithWebSocketServer("ws://a.b/mqtt").WithTimeout(TimeSpan.FromSeconds(2)).Build();
                 await client.ConnectAsync(options).ConfigureAwait(false);
             }
         }

Source/MQTTnet.Tests/MqttApplicationMessageBuilder_Tests.cs

@@ -4,7 +4,6 @@
 
 using System;
 using System.IO;
-using System.Linq;
 using System.Text;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using MQTTnet.Protocol;
@@ -12,7 +11,7 @@ using MQTTnet.Protocol;
 namespace MQTTnet.Tests
 {
     [TestClass]
-    public sealed class MqttApplicationMessageBuilder_Tests
+    public class MqttApplicationMessageBuilder_Tests
     {
         [TestMethod]
         public void CreateApplicationMessage_TopicOnly()
@@ -30,7 +29,7 @@ namespace MQTTnet.Tests
             Assert.AreEqual("xyz", message.Topic);
             Assert.IsFalse(message.Retain);
             Assert.AreEqual(MqttQualityOfServiceLevel.AtMostOnce, message.QualityOfServiceLevel);
-            Assert.AreEqual(Encoding.UTF8.GetString(message.PayloadSegment.ToArray()), "00:06:00");
+            Assert.AreEqual(Encoding.UTF8.GetString(message.Payload), "00:06:00");
         }
 
         [TestMethod]
@@ -42,7 +41,7 @@ namespace MQTTnet.Tests
             Assert.AreEqual("123", message.Topic);
             Assert.IsFalse(message.Retain);
             Assert.AreEqual(MqttQualityOfServiceLevel.AtMostOnce, message.QualityOfServiceLevel);
-            Assert.AreEqual(Encoding.UTF8.GetString(message.PayloadSegment.ToArray()), "Hello");
+            Assert.AreEqual(Encoding.UTF8.GetString(message.Payload), "Hello");
         }
 
         [TestMethod]

Source/MQTTnet.Tests/Server/HotSwapCerts_Tests.cs

@@ -1,445 +0,0 @@
-#if !(NET452 || NET461)
-using System;
-using System.Collections.Concurrent;
-using System.Diagnostics;
-using System.Linq;
-using System.Net;
-using System.Net.Security;
-using System.Security.Authentication;
-using System.Security.Cryptography;
-using System.Security.Cryptography.X509Certificates;
-using System.Threading;
-using System.Threading.Tasks;
-using Microsoft.VisualStudio.TestTools.UnitTesting;
-using MQTTnet.Certificates;
-using MQTTnet.Client;
-using MQTTnet.Formatter;
-using MQTTnet.Protocol;
-using MQTTnet.Server;
-
-namespace MQTTnet.Tests.Server
-{
-    // missing certificate builder api means tests won't work for older frameworks
-
-    [TestClass]
-    public sealed class HotSwapCerts_Tests
-    {
-        static readonly TimeSpan DefaultTimeout = TimeSpan.FromSeconds(10);
-
-        [TestMethod]
-        public async Task ClientCertChangeWithoutServerUpdateFailsReconnect()
-        {
-            using (var server = new ServerTestHarness())
-            using (var client01 = new ClientTestHarness())
-            {
-                server.InstallNewClientCert(client01.GetCurrentClientCert());
-                client01.InstallNewServerCert(server.GetCurrentServerCert());
-
-                await server.StartServer();
-
-                await client01.Connect();
-
-                client01.WaitForConnectOrFail(DefaultTimeout);
-
-                client01.HotSwapClientCert();
-                server.ForceDisconnectAsync(client01).Wait(DefaultTimeout);
-                client01.WaitForDisconnectOrFail(DefaultTimeout);
-
-                client01.WaitForConnectToFail(DefaultTimeout);
-            }
-        }
-
-        [TestMethod]
-        public async Task ClientCertChangeWithServerUpdateAcceptsReconnect()
-        {
-            using (var server = new ServerTestHarness())
-            using (var client01 = new ClientTestHarness())
-            {
-                server.InstallNewClientCert(client01.GetCurrentClientCert());
-                client01.InstallNewServerCert(server.GetCurrentServerCert());
-
-                await server.StartServer();
-
-                await client01.Connect();
-
-                client01.WaitForConnectOrFail(DefaultTimeout);
-
-                client01.HotSwapClientCert();
-                server.ForceDisconnectAsync(client01).Wait(DefaultTimeout);
-                client01.WaitForDisconnectOrFail(DefaultTimeout);
-
-                server.InstallNewClientCert(client01.GetCurrentClientCert());
-
-                client01.WaitForConnectOrFail(DefaultTimeout);
-            }
-        }
-
-        [TestMethod]
-        public async Task ServerCertChangeWithClientCertUpdateAllowsReconnect()
-        {
-            using (var server = new ServerTestHarness())
-            using (var client01 = new ClientTestHarness())
-            {
-                server.InstallNewClientCert(client01.GetCurrentClientCert());
-                client01.InstallNewServerCert(server.GetCurrentServerCert());
-
-                await server.StartServer();
-                await client01.Connect();
-
-                client01.WaitForConnectOrFail(DefaultTimeout);
-                server.HotSwapServerCert();
-
-                server.ForceDisconnectAsync(client01).Wait(DefaultTimeout);
-                client01.WaitForDisconnectOrFail(DefaultTimeout);
-                client01.InstallNewServerCert(server.GetCurrentServerCert());
-
-                client01.WaitForConnectOrFail(DefaultTimeout);
-            }
-        }
-
-        [TestMethod]
-        public async Task ServerCertChangeWithoutClientCertUpdateFailsReconnect()
-        {
-            using (var server = new ServerTestHarness())
-            using (var client01 = new ClientTestHarness())
-            {
-                server.InstallNewClientCert(client01.GetCurrentClientCert());
-                client01.InstallNewServerCert(server.GetCurrentServerCert());
-
-                await server.StartServer();
-                await client01.Connect();
-
-                client01.WaitForConnectOrFail(DefaultTimeout);
-                server.HotSwapServerCert();
-
-                server.ForceDisconnectAsync(client01).Wait(DefaultTimeout);
-                client01.WaitForDisconnectOrFail(DefaultTimeout);
-
-                client01.WaitForConnectToFail(DefaultTimeout);
-            }
-        }
-
-        static X509Certificate2 CreateSelfSignedCertificate(string oid)
-        {
-            var sanBuilder = new SubjectAlternativeNameBuilder();
-            sanBuilder.AddIpAddress(IPAddress.Loopback);
-            sanBuilder.AddIpAddress(IPAddress.IPv6Loopback);
-            sanBuilder.AddDnsName("localhost");
-
-            using (var rsa = RSA.Create())
-            {
-                var certRequest = new CertificateRequest("CN=localhost", rsa, HashAlgorithmName.SHA512, RSASignaturePadding.Pkcs1);
-
-                certRequest.CertificateExtensions.Add(
-                    new X509KeyUsageExtension(X509KeyUsageFlags.DataEncipherment | X509KeyUsageFlags.KeyEncipherment | X509KeyUsageFlags.DigitalSignature, false));
-
-                certRequest.CertificateExtensions.Add(new X509EnhancedKeyUsageExtension(new OidCollection { new Oid(oid) }, false));
-
-                certRequest.CertificateExtensions.Add(sanBuilder.Build());
-
-                using (var certificate = certRequest.CreateSelfSigned(DateTimeOffset.Now.AddMinutes(-10), DateTimeOffset.Now.AddMinutes(10)))
-                {
-                    var pfxCertificate = new X509Certificate2(
-                        certificate.Export(X509ContentType.Pfx),
-                        (string)null,
-                        X509KeyStorageFlags.MachineKeySet | X509KeyStorageFlags.Exportable);
-
-                    return pfxCertificate;
-                }
-            }
-        }
-
-        class ClientTestHarness : IDisposable
-        {
-            readonly HotSwappableClientCertProvider _hotSwapClient = new HotSwappableClientCertProvider();
-            IMqttClient _client;
-
-            public string ClientId => _client.Options.ClientId;
-
-            public void ClearServerCerts()
-            {
-                _hotSwapClient.ClearServerCerts();
-            }
-
-            public Task Connect()
-            {
-                return Run_Client_Connection();
-            }
-
-            public void Dispose()
-            {
-                _client.Dispose();
-            }
-
-            public X509Certificate2 GetCurrentClientCert()
-            {
-                var result = _hotSwapClient.GetCertificates()[0];
-                return new X509Certificate2(result);
-            }
-
-            public void HotSwapClientCert()
-            {
-                _hotSwapClient.HotSwapCert();
-            }
-
-            public void InstallNewServerCert(X509Certificate2 serverCert)
-            {
-                _hotSwapClient.InstallNewServerCert(serverCert);
-            }
-
-            public void WaitForConnectOrFail(TimeSpan timeout)
-            {
-                if (!_client.IsConnected)
-                {
-                    _client.ReconnectAsync().Wait(timeout);
-                }
-
-                WaitForConnect(timeout);
-
-                Assert.IsNotNull(_client, "Client was never initialized");
-                Assert.IsTrue(_client.IsConnected, $"Client connection failed after {timeout}");
-            }
-
-            public void WaitForConnectToFail(TimeSpan timeout)
-            {
-                Assert.IsFalse(_client.IsConnected, "Client should be disconnected before waiting for connect.");
-
-                WaitForConnect(timeout);
-
-                Assert.IsNotNull(_client, "Client was never initialized");
-                Assert.IsFalse(_client.IsConnected, "Client connection success but test wanted fail");
-            }
-
-            public void WaitForDisconnect(TimeSpan timeout)
-            {
-                var timer = Stopwatch.StartNew();
-                while ((_client == null || _client.IsConnected) && timer.Elapsed < timeout)
-                {
-                    Thread.Sleep(5);
-                }
-            }
-
-            public void WaitForDisconnectOrFail(TimeSpan timeout)
-            {
-                WaitForDisconnect(timeout);
-
-                Assert.IsNotNull(_client, "Client was never initialized");
-                Assert.IsFalse(_client.IsConnected, $"Client connection should have disconnected after {timeout}");
-            }
-
-            async Task Run_Client_Connection()
-            {
-                var optionsBuilder = new MqttClientOptionsBuilder()
-                    .WithTlsOptions(
-                        o => o.WithClientCertificatesProvider(_hotSwapClient)
-                            .WithCertificateValidationHandler(_hotSwapClient.OnCertificateValidation)
-                            .WithSslProtocols(SslProtocols.Tls12))
-                    .WithTcpServer("localhost")
-                    .WithCleanSession()
-                    .WithProtocolVersion(MqttProtocolVersion.V500);
-
-                var mqttClientOptions = optionsBuilder.Build();
-
-                var factory = new MqttFactory();
-                var mqttClient = factory.CreateMqttClient();
-                _client = mqttClient;
-
-                await mqttClient.ConnectAsync(mqttClientOptions);
-            }
-
-            void WaitForConnect(TimeSpan timeout)
-            {
-                var timer = Stopwatch.StartNew();
-                while ((_client == null || !_client.IsConnected) && timer.Elapsed < timeout)
-                {
-                    Thread.Sleep(5);
-                }
-            }
-        }
-
-        class ServerTestHarness : IDisposable
-        {
-            readonly HotSwappableServerCertProvider _hotSwapServer = new HotSwappableServerCertProvider();
-
-            MqttServer _server;
-
-            public void ClearClientCerts()
-            {
-                _hotSwapServer.ClearClientCerts();
-            }
-
-            public void Dispose()
-            {
-                if (_server != null)
-                {
-                    _server.StopAsync().Wait();
-                    _server.Dispose();
-                }
-
-                if (_hotSwapServer != null)
-                {
-                    _hotSwapServer.Dispose();
-                }
-            }
-
-            public async Task ForceDisconnectAsync(ClientTestHarness client)
-            {
-                await _server.DisconnectClientAsync(client.ClientId, MqttDisconnectReasonCode.UnspecifiedError);
-            }
-
-            public X509Certificate2 GetCurrentServerCert()
-            {
-                return _hotSwapServer.GetCertificate();
-            }
-
-            public void HotSwapServerCert()
-            {
-                _hotSwapServer.HotSwapCert();
-            }
-
-            public void InstallNewClientCert(X509Certificate2 serverCert)
-            {
-                _hotSwapServer.InstallNewClientCert(serverCert);
-            }
-
-            public async Task StartServer()
-            {
-                var mqttFactory = new MqttFactory();
-
-                var mqttServerOptions = new MqttServerOptionsBuilder().WithEncryptionCertificate(_hotSwapServer)
-                    .WithRemoteCertificateValidationCallback(_hotSwapServer.RemoteCertificateValidationCallback)
-                    .WithEncryptedEndpoint()
-                    .Build();
-
-                mqttServerOptions.TlsEndpointOptions.ClientCertificateRequired = true;
-                _server = mqttFactory.CreateMqttServer(mqttServerOptions);
-                await _server.StartAsync();
-            }
-        }
-
-        class HotSwappableClientCertProvider : IMqttClientCertificatesProvider
-        {
-            X509Certificate2Collection _certificates;
-            ConcurrentBag<X509Certificate2> ServerCerts = new ConcurrentBag<X509Certificate2>();
-
-            public HotSwappableClientCertProvider()
-            {
-                _certificates = new X509Certificate2Collection(CreateSelfSignedCertificate("1.3.6.1.5.5.7.3.2"));
-            }
-
-            public void ClearServerCerts()
-            {
-                ServerCerts = new ConcurrentBag<X509Certificate2>();
-            }
-
-            public X509CertificateCollection GetCertificates()
-            {
-                return new X509Certificate2Collection(_certificates);
-            }
-
-            public void HotSwapCert()
-            {
-                var newCert = new X509Certificate2Collection(CreateSelfSignedCertificate("1.3.6.1.5.5.7.3.2"));
-                var oldCerts = Interlocked.Exchange(ref _certificates, newCert);
-            }
-
-            public void InstallNewServerCert(X509Certificate2 serverCert)
-            {
-                ServerCerts.Add(serverCert);
-            }
-
-            public bool OnCertificateValidation(MqttClientCertificateValidationEventArgs certContext)
-            {
-                var serverCerts = ServerCerts.ToArray();
-
-                var providedCert = certContext.Certificate.GetRawCertData();
-                for (int i = 0, n = serverCerts.Length; i < n; i++)
-                {
-                    var currentcert = serverCerts[i];
-
-                    if (currentcert.RawData.SequenceEqual(providedCert))
-                    {
-                        return true;
-                    }
-                }
-
-                return false;
-            }
-
-            void Dispose()
-            {
-                if (_certificates != null)
-                {
-                    foreach (var certs in _certificates)
-                    {
-#if !NET452
-                        certs.Dispose();
-#endif
-                    }
-                }
-            }
-        }
-
-        class HotSwappableServerCertProvider : ICertificateProvider, IDisposable
-        {
-            X509Certificate2 _certificate;
-            ConcurrentBag<X509Certificate2> ClientCerts = new ConcurrentBag<X509Certificate2>();
-
-            public HotSwappableServerCertProvider()
-            {
-                _certificate = CreateSelfSignedCertificate("1.3.6.1.5.5.7.3.1");
-            }
-
-            public void ClearClientCerts()
-            {
-                ClientCerts = new ConcurrentBag<X509Certificate2>();
-            }
-
-            public void Dispose()
-            {
-#if !NET452
-                _certificate.Dispose();
-#endif
-            }
-
-            public X509Certificate2 GetCertificate()
-            {
-                return _certificate;
-            }
-
-            public void HotSwapCert()
-            {
-                var newCert = CreateSelfSignedCertificate("1.3.6.1.5.5.7.3.1");
-                var oldCert = Interlocked.Exchange(ref _certificate, newCert);
-#if !NET452
-                oldCert.Dispose();
-#endif
-            }
-
-            public void InstallNewClientCert(X509Certificate2 certificate)
-            {
-                ClientCerts.Add(certificate);
-            }
-
-            public bool RemoteCertificateValidationCallback(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)
-            {
-                var serverCerts = ClientCerts.ToArray();
-
-                var providedCert = certificate.GetRawCertData();
-                for (int i = 0, n = serverCerts.Length; i < n; i++)
-                {
-                    var currentCert = serverCerts[i];
-
-                    if (currentCert.RawData.SequenceEqual(providedCert))
-                    {
-                        return true;
-                    }
-                }
-
-                return false;
-            }
-        }
-    }
-}
-
-#endif

Source/MQTTnet/Client/MqttClient.cs

@@ -140,7 +140,6 @@ namespace MQTTnet.Client
                 if (connectResult.ResultCode != MqttClientConnectResultCode.Success)
                 {
                     _logger.Warning("Connecting failed: {0}", connectResult.ResultCode);
-                    await DisconnectInternal(null, null, connectResult).ConfigureAwait(false);
                     return connectResult;
                 }
 
@@ -322,14 +321,14 @@ namespace MQTTnet.Client
                 MqttTopicValidator.ThrowIfInvalidSubscribe(topicFilter.Topic);
             }
 
-            ThrowIfDisposed();
-            ThrowIfNotConnected();
-            
             if (Options.ValidateFeatures)
             {
                 MqttClientSubscribeOptionsValidator.ThrowIfNotSupported(options, _adapter.PacketFormatterAdapter.ProtocolVersion);
             }
 
+            ThrowIfDisposed();
+            ThrowIfNotConnected();
+
             var subscribePacket = MqttPacketFactories.Subscribe.Create(options);
             subscribePacket.PacketIdentifier = _packetIdentifierProvider.GetNextPacketIdentifier();
 
@@ -466,10 +465,11 @@ namespace MQTTnet.Client
             // did send a proper ACK packet with a non success response.
             if (options.ThrowOnNonSuccessfulConnectResponse)
             {
+                _logger.Warning(
+                    "Client will now throw an _MqttConnectingFailedException_. This is obsolete and will be removed in the future. Consider setting _ThrowOnNonSuccessfulResponseFromServer=False_ in client options.");
+
                 if (result.ResultCode != MqttClientConnectResultCode.Success)
                 {
-                    _logger.Warning(
-                        "Client will now throw an _MqttConnectingFailedException_. This is obsolete and will be removed in the future. Consider setting _ThrowOnNonSuccessfulResponseFromServer=False_ in client options.");
                     throw new MqttConnectingFailedException($"Connecting with MQTT server failed ({result.ResultCode}).", null, result);
                 }
             }
@@ -881,6 +881,7 @@ namespace MQTTnet.Client
 
             _lastPacketSentTimestamp = DateTime.UtcNow;
 
+            //ThrowIfNotConnected();
             return _adapter.SendPacketAsync(packet, cancellationToken);
         }
 
@@ -1060,4 +1061,4 @@ namespace MQTTnet.Client
             }
         }
     }
-}
+}

Source/MQTTnet/Client/Options/DefaultMqttCertificatesProvider.cs

@@ -1,36 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-// See the LICENSE file in the project root for more information.
-
-using System.Collections.Generic;
-using System.Security.Cryptography.X509Certificates;
-
-namespace MQTTnet.Client
-{
-    public sealed class DefaultMqttCertificatesProvider : IMqttClientCertificatesProvider
-    {
-        readonly X509Certificate2Collection _certificates;
-
-        public DefaultMqttCertificatesProvider(X509Certificate2Collection certificates)
-        {
-            _certificates = certificates;
-        }
-
-        public DefaultMqttCertificatesProvider(IEnumerable<X509Certificate> certificates)
-        {
-            if (certificates != null)
-            {
-                _certificates = new X509Certificate2Collection();
-                foreach (var certificate in certificates)
-                {
-                    _certificates.Add(certificate);
-                }
-            }
-        }
-
-        public X509CertificateCollection GetCertificates()
-        {
-            return _certificates;
-        }
-    }
-}

Source/MQTTnet/Client/Options/IMqttClientCertificatesProvider.cs

@@ -1,11 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-// See the LICENSE file in the project root for more information.
-
-namespace MQTTnet.Client
-{
-    public interface IMqttClientCertificatesProvider
-    {
-        System.Security.Cryptography.X509Certificates.X509CertificateCollection GetCertificates();
-    }
-}

Source/MQTTnet/Client/Options/MqttClientCertificateValidationEventArgs.cs

@@ -14,14 +14,8 @@ namespace MQTTnet.Client
 
         public X509Chain Chain { get; set; }
 
-        public IMqttClientChannelOptions ClientOptions { get; set; }
-#if NET452 || NET461 || NET48
-        /// <summary>
-        ///     Can be a host string name or an object derived from WebRequest.
-        /// </summary>
-        public object Sender { get; set; }
-#endif
-
         public SslPolicyErrors SslPolicyErrors { get; set; }
+
+        public IMqttClientChannelOptions ClientOptions { get; set; }
     }
-}
+}

Source/MQTTnet/Client/Options/MqttClientOptionsBuilder.cs

@@ -15,14 +15,10 @@ namespace MQTTnet.Client
     public sealed class MqttClientOptionsBuilder
     {
         readonly MqttClientOptions _options = new MqttClientOptions();
-
-        [Obsolete] MqttClientWebSocketProxyOptions _proxyOptions;
+        MqttClientWebSocketProxyOptions _proxyOptions;
 
         MqttClientTcpOptions _tcpOptions;
-        MqttClientTlsOptions _tlsOptions;
-
-        [Obsolete] MqttClientOptionsBuilderTlsParameters _tlsParameters;
-
+        MqttClientOptionsBuilderTlsParameters _tlsParameters;
         MqttClientWebSocketOptions _webSocketOptions;
 
         public MqttClientOptions Build()
@@ -32,12 +28,11 @@ namespace MQTTnet.Client
                 throw new InvalidOperationException("A channel must be set.");
             }
 
-            var tlsOptions = _tlsOptions;
             if (_tlsParameters != null)
             {
                 if (_tlsParameters?.UseTls == true)
                 {
-                    tlsOptions = new MqttClientTlsOptions
+                    var tlsOptions = new MqttClientTlsOptions
                     {
                         UseTls = true,
                         SslProtocol = _tlsParameters.SslProtocol,
@@ -45,21 +40,26 @@ namespace MQTTnet.Client
                         CertificateValidationHandler = _tlsParameters.CertificateValidationHandler,
                         IgnoreCertificateChainErrors = _tlsParameters.IgnoreCertificateChainErrors,
                         IgnoreCertificateRevocationErrors = _tlsParameters.IgnoreCertificateRevocationErrors,
-                        ClientCertificatesProvider = _tlsParameters.CertificatesProvider,
+#if WINDOWS_UWP
+                        Certificates = _tlsParameters.Certificates?.Select(c => c.ToArray()).ToList(),
+#else
+                        Certificates = _tlsParameters.Certificates?.ToList(),
+#endif
+
 #if NETCOREAPP3_1_OR_GREATER
                         ApplicationProtocols = _tlsParameters.ApplicationProtocols,
 #endif
                     };
-                }
-            }
 
-            if (_tcpOptions != null)
-            {
-                _tcpOptions.TlsOptions = tlsOptions;
-            }
-            else if (_webSocketOptions != null)
-            {
-                _webSocketOptions.TlsOptions = tlsOptions;
+                    if (_tcpOptions != null)
+                    {
+                        _tcpOptions.TlsOptions = tlsOptions;
+                    }
+                    else if (_webSocketOptions != null)
+                    {
+                        _webSocketOptions.TlsOptions = tlsOptions;
+                    }
+                }
             }
 
             if (_proxyOptions != null)
@@ -78,7 +78,17 @@ namespace MQTTnet.Client
 
             return _options;
         }
-
+        
+        /// <summary>
+        /// The client will not throw an exception when the MQTT server responses with a non success ACK packet.
+        /// This will become the default behavior in future versions of the library.
+        /// </summary>
+        public MqttClientOptionsBuilder WithoutThrowOnNonSuccessfulConnectResponse()
+        {
+            _options.ThrowOnNonSuccessfulConnectResponse = false;
+            return this;
+        }
+        
         public MqttClientOptionsBuilder WithAuthentication(string method, byte[] data)
         {
             _options.AuthenticationMethod = method;
@@ -110,7 +120,6 @@ namespace MQTTnet.Client
             return this;
         }
 
-        [Obsolete("Use WithTcpServer(... configure) or WithWebSocketServer(... configure) instead.")]
         public MqttClientOptionsBuilder WithConnectionUri(Uri uri)
         {
             if (uri == null)
@@ -127,16 +136,12 @@ namespace MQTTnet.Client
                     break;
 
                 case "mqtts":
-                    WithTcpServer(uri.Host, port)
-                        .WithTlsOptions(
-                            o =>
-                            {
-                            });
+                    WithTcpServer(uri.Host, port).WithTls();
                     break;
 
                 case "ws":
                 case "wss":
-                    WithWebSocketServer(o => o.WithUri(uri.ToString()));
+                    WithWebSocketServer(uri.ToString());
                     break;
 
                 default:
@@ -154,7 +159,6 @@ namespace MQTTnet.Client
             return this;
         }
 
-        [Obsolete("Use WithTcpServer(... configure) or WithWebSocketServer(... configure) instead.")]
         public MqttClientOptionsBuilder WithConnectionUri(string uri)
         {
             return WithConnectionUri(new Uri(uri, UriKind.Absolute));
@@ -218,16 +222,6 @@ namespace MQTTnet.Client
             return this;
         }
 
-        /// <summary>
-        ///     The client will not throw an exception when the MQTT server responses with a non success ACK packet.
-        ///     This will become the default behavior in future versions of the library.
-        /// </summary>
-        public MqttClientOptionsBuilder WithoutThrowOnNonSuccessfulConnectResponse()
-        {
-            _options.ThrowOnNonSuccessfulConnectResponse = false;
-            return this;
-        }
-
         public MqttClientOptionsBuilder WithProtocolVersion(MqttProtocolVersion value)
         {
             if (value == MqttProtocolVersion.Unknown)
@@ -239,7 +233,6 @@ namespace MQTTnet.Client
             return this;
         }
 
-        [Obsolete("Use WithWebSocketServer(... configure) instead.")]
         public MqttClientOptionsBuilder WithProxy(
             string address,
             string username = null,
@@ -261,7 +254,6 @@ namespace MQTTnet.Client
             return this;
         }
 
-        [Obsolete("Use WithWebSocketServer(... configure) instead.")]
         public MqttClientOptionsBuilder WithProxy(Action<MqttClientWebSocketProxyOptions> optionsBuilder)
         {
             if (optionsBuilder == null)
@@ -332,20 +324,17 @@ namespace MQTTnet.Client
             return this;
         }
 
-        [Obsolete("Use WithTlsOptions(... configure) instead.")]
         public MqttClientOptionsBuilder WithTls(MqttClientOptionsBuilderTlsParameters parameters)
         {
             _tlsParameters = parameters;
             return this;
         }
 
-        [Obsolete("Use WithTlsOptions(... configure) instead.")]
         public MqttClientOptionsBuilder WithTls()
         {
             return WithTls(new MqttClientOptionsBuilderTlsParameters { UseTls = true });
         }
 
-        [Obsolete("Use WithTlsOptions(... configure) instead.")]
         public MqttClientOptionsBuilder WithTls(Action<MqttClientOptionsBuilderTlsParameters> optionsBuilder)
         {
             if (optionsBuilder == null)
@@ -362,26 +351,6 @@ namespace MQTTnet.Client
             return this;
         }
 
-        public MqttClientOptionsBuilder WithTlsOptions(MqttClientTlsOptions tlsOptions)
-        {
-            _tlsOptions = tlsOptions;
-            return this;
-        }
-
-        public MqttClientOptionsBuilder WithTlsOptions(Action<MqttClientTlsOptionsBuilder> configure)
-        {
-            if (configure == null)
-            {
-                throw new ArgumentNullException(nameof(configure));
-            }
-
-            var builder = new MqttClientTlsOptionsBuilder();
-            configure.Invoke(builder);
-
-            _tlsOptions = builder.Build();
-            return this;
-        }
-
         public MqttClientOptionsBuilder WithTopicAliasMaximum(ushort topicAliasMaximum)
         {
             _options.TopicAliasMaximum = topicAliasMaximum;
@@ -413,7 +382,6 @@ namespace MQTTnet.Client
             return this;
         }
 
-        [Obsolete("Use WithWebSocketServer(... configure) instead.")]
         public MqttClientOptionsBuilder WithWebSocketServer(string uri, MqttClientOptionsBuilderWebSocketParameters parameters = null)
         {
             _webSocketOptions = new MqttClientWebSocketOptions
@@ -426,21 +394,6 @@ namespace MQTTnet.Client
             return this;
         }
 
-        public MqttClientOptionsBuilder WithWebSocketServer(Action<MqttClientWebSocketOptionsBuilder> configure)
-        {
-            if (configure == null)
-            {
-                throw new ArgumentNullException(nameof(configure));
-            }
-
-            var webSocketOptionsBuilder = new MqttClientWebSocketOptionsBuilder();
-            configure.Invoke(webSocketOptionsBuilder);
-
-            _webSocketOptions = webSocketOptionsBuilder.Build();
-            return this;
-        }
-
-        [Obsolete("Use WithWebSocketServer(... configure) instead.")]
         public MqttClientOptionsBuilder WithWebSocketServer(Action<MqttClientWebSocketOptions> optionsBuilder)
         {
             if (optionsBuilder == null)
@@ -472,12 +425,6 @@ namespace MQTTnet.Client
             return this;
         }
 
-        public MqttClientOptionsBuilder WithWillMessageExpiryInterval(uint willMessageExpiryInterval)
-        {
-            _options.WillMessageExpiryInterval = willMessageExpiryInterval;
-            return this;
-        }
-
         public MqttClientOptionsBuilder WithWillPayload(byte[] willPayload)
         {
             _options.WillPayload = willPayload;

Source/MQTTnet/Client/Options/MqttClientOptionsBuilderTlsParameters.cs

@@ -5,14 +5,12 @@
 using System;
 using System.Collections.Generic;
 using System.Security.Authentication;
+using System.Security.Cryptography.X509Certificates;
 
 namespace MQTTnet.Client
 {
-    [Obsolete("Use methods from MqttClientOptionsBuilder instead.")]
     public sealed class MqttClientOptionsBuilderTlsParameters
     {
-        IEnumerable<System.Security.Cryptography.X509Certificates.X509Certificate> _obsoleteCertificates;
-
         public bool UseTls { get; set; }
 
         public Func<MqttClientCertificateValidationEventArgs, bool> CertificateValidationHandler { get; set; }
@@ -26,24 +24,7 @@ namespace MQTTnet.Client
 #if WINDOWS_UWP
         public IEnumerable<IEnumerable<byte>> Certificates { get; set; }
 #else
-        [Obsolete("Use CertificatesProvider instead.")]
-        public IEnumerable<System.Security.Cryptography.X509Certificates.X509Certificate> Certificates
-        {
-            get => _obsoleteCertificates;
-            set
-            {
-                _obsoleteCertificates = value;
-
-                if (value == null)
-                {
-                    CertificatesProvider = null;
-                }
-                else
-                {
-                    CertificatesProvider = new DefaultMqttCertificatesProvider(value);
-                }
-            }
-        }
+        public IEnumerable<X509Certificate> Certificates { get; set; }
 #endif
 
 #if NETCOREAPP3_1_OR_GREATER
@@ -55,7 +36,5 @@ namespace MQTTnet.Client
         public bool IgnoreCertificateChainErrors { get; set; }
 
         public bool IgnoreCertificateRevocationErrors { get; set; }
-
-        public IMqttClientCertificatesProvider CertificatesProvider { get; set; }
     }
 }

Source/MQTTnet/Client/Options/MqttClientOptionsBuilderWebSocketParameters.cs

@@ -2,13 +2,11 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-using System;
 using System.Collections.Generic;
 using System.Net;
 
 namespace MQTTnet.Client
 {
-    [Obsolete("Use dedicated methods in MqttClientOptionsBuilder.")]
     public class MqttClientOptionsBuilderWebSocketParameters
     {
         public IDictionary<string, string> RequestHeaders { get; set; }

Source/MQTTnet/Client/Options/MqttClientTcpOptionsExtensions.cs

@@ -17,7 +17,7 @@ namespace MQTTnet.Client
                 return options.Port.Value;
             }
 
-            return !(options.TlsOptions?.UseTls ?? false) ? 1883 : 8883;
+            return !options.TlsOptions.UseTls ? 1883 : 8883;
         }
     }
 }

Source/MQTTnet/Client/Options/MqttClientTlsOptions.cs

@@ -24,13 +24,11 @@ namespace MQTTnet.Client
 
         public X509RevocationMode RevocationMode { get; set; } = X509RevocationMode.Online;
 
-        /// <summary>
-        ///     Gets or sets the provider for certificates.
-        ///     This provider gets called whenever the client wants to connect
-        ///     with the server and requires certificates for authentication.
-        ///     The implementation may return different certificates each time.
-        /// </summary>
-        public IMqttClientCertificatesProvider ClientCertificatesProvider { get; set; }
+#if WINDOWS_UWP
+        public List<byte[]> Certificates { get; set; }
+#else
+        public List<X509Certificate> Certificates { get; set; }
+#endif
 
 #if NETCOREAPP3_1_OR_GREATER
         public List<SslApplicationProtocol> ApplicationProtocols { get; set; }

Source/MQTTnet/Client/Options/MqttClientTlsOptionsBuilder.cs

@@ -1,136 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-// See the LICENSE file in the project root for more information.
-
-using System;
-using System.Collections.Generic;
-using System.Security.Authentication;
-using System.Security.Cryptography.X509Certificates;
-#if NETCOREAPP3_1_OR_GREATER
-using System.Net.Security;
-#endif
-
-namespace MQTTnet.Client
-{
-    public sealed class MqttClientTlsOptionsBuilder
-    {
-        readonly MqttClientTlsOptions _tlsOptions = new MqttClientTlsOptions
-        {
-            // If someone used this builder the change is very very high that TLS
-            // should be actually used.
-            UseTls = true
-        };
-
-        public MqttClientTlsOptions Build()
-        {
-            return _tlsOptions;
-        }
-
-        public MqttClientTlsOptionsBuilder UseTls(bool useTls = true)
-        {
-            _tlsOptions.UseTls = useTls;
-            return this;
-        }
-
-        public MqttClientTlsOptionsBuilder WithAllowUntrustedCertificates(bool allowUntrustedCertificates = true)
-        {
-            _tlsOptions.AllowUntrustedCertificates = allowUntrustedCertificates;
-            return this;
-        }
-
-        public MqttClientTlsOptionsBuilder WithCertificateValidationHandler(Func<MqttClientCertificateValidationEventArgs, bool> certificateValidationHandler)
-        {
-            if (certificateValidationHandler == null)
-            {
-                throw new ArgumentNullException(nameof(certificateValidationHandler));
-            }
-
-            _tlsOptions.CertificateValidationHandler = certificateValidationHandler;
-            return this;
-        }
-
-        public MqttClientTlsOptionsBuilder WithClientCertificates(IEnumerable<X509Certificate2> certificates)
-        {
-            if (certificates == null)
-            {
-                throw new ArgumentNullException(nameof(certificates));
-            }
-
-            _tlsOptions.ClientCertificatesProvider = new DefaultMqttCertificatesProvider(certificates);
-            return this;
-        }
-
-        public MqttClientTlsOptionsBuilder WithClientCertificates(X509Certificate2Collection certificates)
-        {
-            if (certificates == null)
-            {
-                throw new ArgumentNullException(nameof(certificates));
-            }
-
-            _tlsOptions.ClientCertificatesProvider = new DefaultMqttCertificatesProvider(certificates);
-            return this;
-        }
-
-        public MqttClientTlsOptionsBuilder WithClientCertificatesProvider(IMqttClientCertificatesProvider clientCertificatesProvider)
-        {
-            _tlsOptions.ClientCertificatesProvider = clientCertificatesProvider;
-            return this;
-        }
-
-        public MqttClientTlsOptionsBuilder WithIgnoreCertificateChainErrors(bool ignoreCertificateChainErrors = true)
-        {
-            _tlsOptions.IgnoreCertificateChainErrors = ignoreCertificateChainErrors;
-            return this;
-        }
-
-        public MqttClientTlsOptionsBuilder WithIgnoreCertificateRevocationErrors(bool ignoreCertificateRevocationErrors = true)
-        {
-            _tlsOptions.IgnoreCertificateRevocationErrors = ignoreCertificateRevocationErrors;
-            return this;
-        }
-
-        public MqttClientTlsOptionsBuilder WithRevocationMode(X509RevocationMode revocationMode)
-        {
-            _tlsOptions.RevocationMode = revocationMode;
-            return this;
-        }
-
-        public MqttClientTlsOptionsBuilder WithSslProtocols(SslProtocols sslProtocols)
-        {
-            _tlsOptions.SslProtocol = sslProtocols;
-            return this;
-        }
-
-        public MqttClientTlsOptionsBuilder WithTargetHost(string targetHost)
-        {
-            _tlsOptions.TargetHost = targetHost;
-            return this;
-        }
-
-#if NETCOREAPP3_1_OR_GREATER
-        public MqttClientTlsOptionsBuilder WithAllowRenegotiation(bool allowRenegotiation = true)
-        {
-            _tlsOptions.AllowRenegotiation = allowRenegotiation;
-            return this;
-        }
-
-        public MqttClientTlsOptionsBuilder WithApplicationProtocols(List<SslApplicationProtocol> applicationProtocols)
-        {
-            _tlsOptions.ApplicationProtocols = applicationProtocols;
-            return this;
-        }
-
-        public MqttClientTlsOptionsBuilder WithCipherSuitesPolicy(CipherSuitesPolicy cipherSuitePolicy)
-        {
-            _tlsOptions.CipherSuitesPolicy = cipherSuitePolicy;
-            return this;
-        }
-
-        public MqttClientTlsOptionsBuilder WithCipherSuitesPolicy(EncryptionPolicy encryptionPolicy)
-        {
-            _tlsOptions.EncryptionPolicy = encryptionPolicy;
-            return this;
-        }
-#endif
-    }
-}

Source/MQTTnet/Client/Options/MqttClientWebSocketOptionsBuilder.cs

@@ -1,85 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-// See the LICENSE file in the project root for more information.
-
-using System;
-using System.Collections.Generic;
-using System.Net;
-
-namespace MQTTnet.Client
-{
-    public sealed class MqttClientWebSocketOptionsBuilder
-    {
-        readonly MqttClientWebSocketOptions _webSocketOptions = new MqttClientWebSocketOptions();
-
-        public MqttClientWebSocketOptions Build()
-        {
-            return _webSocketOptions;
-        }
-
-        public MqttClientWebSocketOptionsBuilder WithCookieContainer(CookieContainer cookieContainer)
-        {
-            _webSocketOptions.CookieContainer = cookieContainer;
-            return this;
-        }
-
-        public MqttClientWebSocketOptionsBuilder WithCookieContainer(ICredentials credentials)
-        {
-            _webSocketOptions.Credentials = credentials;
-            return this;
-        }
-
-        public MqttClientWebSocketOptionsBuilder WithProxyOptions(MqttClientWebSocketProxyOptions proxyOptions)
-        {
-            _webSocketOptions.ProxyOptions = proxyOptions;
-            return this;
-        }
-
-        public MqttClientWebSocketOptionsBuilder WithProxyOptions(Action<MqttClientWebSocketProxyOptionsBuilder> configure)
-        {
-            if (configure == null)
-            {
-                throw new ArgumentNullException(nameof(configure));
-            }
-
-            var proxyOptionsBuilder = new MqttClientWebSocketProxyOptionsBuilder();
-            configure.Invoke(proxyOptionsBuilder);
-
-            _webSocketOptions.ProxyOptions = proxyOptionsBuilder.Build();
-            return this;
-        }
-
-        public MqttClientWebSocketOptionsBuilder WithRequestHeaders(IDictionary<string, string> requestHeaders)
-        {
-            _webSocketOptions.RequestHeaders = requestHeaders;
-            return this;
-        }
-
-        public MqttClientWebSocketOptionsBuilder WithSubProtocols(ICollection<string> subProtocols)
-        {
-            _webSocketOptions.SubProtocols = subProtocols;
-            return this;
-        }
-
-        public MqttClientWebSocketOptionsBuilder WithUri(string uri)
-        {
-            _webSocketOptions.Uri = uri;
-            return this;
-        }
-
-#if !NETSTANDARD1_3
-        public MqttClientWebSocketOptionsBuilder WithKeepAliveInterval(TimeSpan keepAliveInterval)
-        {
-            _webSocketOptions.KeepAliveInterval = keepAliveInterval;
-            return this;
-        }
-#endif
-#if !WINDOWS_UWP && !NETSTANDARD1_3
-        public MqttClientWebSocketOptionsBuilder WithUseDefaultCredentials(bool useDefaultCredentials = true)
-        {
-            _webSocketOptions.UseDefaultCredentials = useDefaultCredentials;
-            return this;
-        }
-#endif
-    }
-}

Source/MQTTnet/Client/Options/MqttClientWebSocketProxyOptionsBuilder.cs

@@ -1,67 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-// See the LICENSE file in the project root for more information.
-
-using System.Collections.Generic;
-using System.Linq;
-
-namespace MQTTnet.Client
-{
-    public sealed class MqttClientWebSocketProxyOptionsBuilder
-    {
-        readonly MqttClientWebSocketProxyOptions _proxyOptions = new MqttClientWebSocketProxyOptions();
-
-        public MqttClientWebSocketProxyOptionsBuilder WithAddress(string address)
-        {
-            _proxyOptions.Address = address;
-            return this;
-        }
-        
-        public MqttClientWebSocketProxyOptionsBuilder WithUsername(string username)
-        {
-            _proxyOptions.Username = username;
-            return this;
-        }
-        
-        public MqttClientWebSocketProxyOptionsBuilder WithPassword(string password)
-        {
-            _proxyOptions.Password = password;
-            return this;
-        }
-        
-        public MqttClientWebSocketProxyOptionsBuilder WithDomain(string domain)
-        {
-            _proxyOptions.Domain = domain;
-            return this;
-        }
-        
-        public MqttClientWebSocketProxyOptionsBuilder WithBypassOnLocal(bool bypassOnLocal = true)
-        {
-            _proxyOptions.BypassOnLocal = bypassOnLocal;
-            return this;
-        }
-        
-        public MqttClientWebSocketProxyOptionsBuilder WithBypassList(string[] bypassList)
-        {
-            _proxyOptions.BypassList = bypassList;
-            return this;
-        }
-        
-        public MqttClientWebSocketProxyOptionsBuilder WithBypassList(IEnumerable<string> bypassList)
-        {
-            _proxyOptions.BypassList = bypassList?.ToArray();
-            return this;
-        }
-        
-        public MqttClientWebSocketProxyOptionsBuilder WithUseDefaultCredentials(bool useDefaultCredentials = true)
-        {
-            _proxyOptions.UseDefaultCredentials = useDefaultCredentials;
-            return this;
-        }
-        
-        public MqttClientWebSocketProxyOptions Build()
-        {
-            return _proxyOptions;
-        }
-    }
-}

Source/MQTTnet/Client/Receiving/MqttApplicationMessageReceivedEventArgs.cs

@@ -77,7 +77,7 @@ namespace MQTTnet.Client
 
         internal MqttPublishPacket PublishPacket { get; set; }
 
-        public Task AcknowledgeAsync(CancellationToken cancellationToken)
+        public Task AcknowledgeAsync(CancellationToken cancellationToken = default)
         {
             if (_acknowledgeHandler == null)
             {

Source/MQTTnet/Implementations/MqttTcpChannel.Uwp.cs

@@ -6,6 +6,8 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Linq;
+using System.Runtime.InteropServices.WindowsRuntime;
 using System.Security.Authentication;
 using System.Security.Cryptography.X509Certificates;
 using System.Threading;
@@ -16,7 +18,6 @@ using Windows.Security.Cryptography.Certificates;
 using MQTTnet.Channel;
 using MQTTnet.Client;
 using MQTTnet.Server;
-using System.Runtime.InteropServices.WindowsRuntime;
 
 namespace MQTTnet.Implementations
 {
@@ -125,19 +126,17 @@ namespace MQTTnet.Implementations
 
         private static Certificate LoadCertificate(IMqttClientChannelOptions options)
         {
-            var certificates = options.TlsOptions?.ClientCertificatesProvider?.GetCertificates();
-
-            if (certificates == null || certificates.Count == 0)
+            if (options.TlsOptions.Certificates == null || !options.TlsOptions.Certificates.Any())
             {
                 return null;
             }
 
-            if (certificates.Count > 1)
+            if (options.TlsOptions.Certificates.Count > 1)
             {
                 throw new NotSupportedException("Only one client certificate is supported when using 'uap10.0'.");
             }
 
-            return new Certificate(certificates[0].Export(X509ContentType.Cert).AsBuffer());
+            return new Certificate(options.TlsOptions.Certificates.First().AsBuffer());
         }
 
         private IEnumerable<ChainValidationResult> ResolveIgnorableServerCertificateErrors()

Source/MQTTnet/Implementations/MqttTcpChannel.cs

@@ -3,6 +3,9 @@
 // See the LICENSE file in the project root for more information.
 
 #if !WINDOWS_UWP
+using MQTTnet.Channel;
+using MQTTnet.Client;
+using MQTTnet.Exceptions;
 using System;
 using System.IO;
 using System.Net.Security;
@@ -11,9 +14,6 @@ using System.Runtime.ExceptionServices;
 using System.Security.Cryptography.X509Certificates;
 using System.Threading;
 using System.Threading.Tasks;
-using MQTTnet.Channel;
-using MQTTnet.Client;
-using MQTTnet.Exceptions;
 using MQTTnet.Internal;
 
 namespace MQTTnet.Implementations
@@ -73,7 +73,7 @@ namespace MQTTnet.Implementations
                 {
                     socket.Bind(_tcpOptions.LocalEndpoint);
                 }
-
+                
                 socket.ReceiveBufferSize = _tcpOptions.BufferSize;
                 socket.SendBufferSize = _tcpOptions.BufferSize;
                 socket.SendTimeout = (int)_clientOptions.Timeout.TotalMilliseconds;
@@ -105,7 +105,7 @@ namespace MQTTnet.Implementations
                     {
                         targetHost = _tcpOptions.Server;
                     }
-
+                    
                     var sslStream = new SslStream(networkStream, false, InternalUserCertificateValidationCallback);
                     try
                     {
@@ -298,7 +298,18 @@ namespace MQTTnet.Implementations
 
         X509CertificateCollection LoadCertificates()
         {
-            return _tcpOptions.TlsOptions.ClientCertificatesProvider?.GetCertificates();
+            if (_tcpOptions.TlsOptions.Certificates == null)
+            {
+                return null;
+            }
+
+            var certificates = new X509CertificateCollection();
+            foreach (var certificate in _tcpOptions.TlsOptions.Certificates)
+            {
+                certificates.Add(certificate);
+            }
+
+            return certificates;
         }
     }
 }

Source/MQTTnet/Implementations/MqttWebSocketChannel.cs

@@ -206,12 +206,16 @@ namespace MQTTnet.Implementations
                 clientWebSocket.Options.Cookies = _options.CookieContainer;
             }
 
-            if (_options.TlsOptions?.UseTls == true)
+            if (_options.TlsOptions?.UseTls == true && _options.TlsOptions?.Certificates != null)
             {
-                var certificates = _options.TlsOptions?.ClientCertificatesProvider?.GetCertificates();
-                if (certificates?.Count > 0)
+                clientWebSocket.Options.ClientCertificates = new X509CertificateCollection();
+                foreach (var certificate in _options.TlsOptions.Certificates)
                 {
-                    clientWebSocket.Options.ClientCertificates = certificates;
+#if WINDOWS_UWP
+                    clientWebSocket.Options.ClientCertificates.Add(new X509Certificate(certificate));
+#else
+                    clientWebSocket.Options.ClientCertificates.Add(certificate);
+#endif
                 }
             }
 
@@ -244,20 +248,12 @@ namespace MQTTnet.Implementations
                 throw new NotSupportedException("Remote certificate validation callback is not supported when using 'netstandard2.0'.");
 #elif WINDOWS_UWP
                 throw new NotSupportedException("Remote certificate validation callback is not supported when using 'uap10.0'.");
-#elif NET452 || NET461 || NET48
-                ServicePointManager.ServerCertificateValidationCallback += (sender, certificate, chain, sslPolicyErrors) => 
-                {
-                    var context = new MqttClientCertificateValidationEventArgs
-                    {
-                        Sender = sender,
-                        Certificate = certificate,
-                        Chain = chain,
-                        SslPolicyErrors = sslPolicyErrors,
-                        ClientOptions = _options
-                    };
-
-                    return certificateValidationHandler(context);
-                };
+#elif NET452
+                throw new NotSupportedException("Remote certificate validation callback is not supported when using 'net452'.");
+#elif NET461
+                throw new NotSupportedException("Remote certificate validation callback is not supported when using 'net461'.");
+#elif NET48
+                throw new NotSupportedException("Remote certificate validation callback is not supported when using 'net48'.");
 #else
                 clientWebSocket.Options.RemoteCertificateValidationCallback = (sender, certificate, chain, sslPolicyErrors) =>
                 {
@@ -276,4 +272,4 @@ namespace MQTTnet.Implementations
             }
         }
     }
-}
+}

Source/MQTTnet/Server/MqttServer.cs

@@ -229,7 +229,13 @@ namespace MQTTnet.Server
             return _clientSessionsManager.GetSessionsStatus();
         }
 
+        [Obsolete("Use InjectApplicationMessageAsync instead.")]
         public Task InjectApplicationMessage(InjectedMqttApplicationMessage injectedApplicationMessage, CancellationToken cancellationToken = default)
+        {
+            return InjectApplicationMessageAsync(injectedApplicationMessage, cancellationToken);
+        }
+        
+        public Task InjectApplicationMessageAsync(InjectedMqttApplicationMessage injectedApplicationMessage, CancellationToken cancellationToken = default)
         {
             if (injectedApplicationMessage == null)
             {

Source/MQTTnet/Server/MqttServerExtensions.cs

@@ -13,12 +13,38 @@ namespace MQTTnet.Server
 {
     public static class MqttServerExtensions
     {
+        [Obsolete("Use InjectApplicationMessageAsync instead.")]
         public static Task InjectApplicationMessage(
             this MqttServer server,
             string topic,
             string payload = null,
             MqttQualityOfServiceLevel qualityOfServiceLevel = MqttQualityOfServiceLevel.AtMostOnce,
             bool retain = false)
+        {
+            return InjectApplicationMessageAsync(server, topic, payload, qualityOfServiceLevel, retain);
+        }
+
+        public static Task InjectApplicationMessageAsync(this MqttServer server, MqttApplicationMessage applicationMessage)
+        {
+            if (server == null)
+            {
+                throw new ArgumentNullException(nameof(server));
+            }
+
+            if (applicationMessage == null)
+            {
+                throw new ArgumentNullException(nameof(applicationMessage));
+            }
+
+            return server.InjectApplicationMessageAsync(new InjectedMqttApplicationMessage(applicationMessage));
+        }
+
+        public static Task InjectApplicationMessageAsync(
+            this MqttServer server,
+            string topic,
+            string payload = null,
+            MqttQualityOfServiceLevel qualityOfServiceLevel = MqttQualityOfServiceLevel.AtMostOnce,
+            bool retain = false)
         {
             if (server == null)
             {
@@ -36,7 +62,7 @@ namespace MQTTnet.Server
                 payloadBuffer = Encoding.UTF8.GetBytes(stringPayload);
             }
 
-            return server.InjectApplicationMessage(
+            return server.InjectApplicationMessageAsync(
                 new InjectedMqttApplicationMessage(
                     new MqttApplicationMessage
                     {