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

# Conflicts:
#	Build/MQTTnet.nuspec
#	Source/MQTTnet/Server/Internal/MqttClientSessionsManager.cs

Tests/MQTTnet.Core.Tests/Server/Assigned_Client_ID_Tests.cs

@@ -2,7 +2,6 @@
 using System.Threading.Tasks;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using MQTTnet.Client;
-using MQTTnet.Client.Options;
 using MQTTnet.Formatter;
 using MQTTnet.Protocol;
 

Tests/MQTTnet.Core.Tests/Server/Events_Tests.cs

@@ -2,7 +2,6 @@
 using System.Threading.Tasks;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using MQTTnet.Client;
-using MQTTnet.Client.Receiving;
 using MQTTnet.Formatter;
 using MQTTnet.Protocol;
 using MQTTnet.Server;

Tests/MQTTnet.Core.Tests/Server/General.cs

@@ -7,11 +7,8 @@ using System.Threading.Tasks;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using MQTTnet.Adapter;
 using MQTTnet.Client;
-using MQTTnet.Client.Connecting;
-using MQTTnet.Client.Disconnecting;
-using MQTTnet.Client.Options;
-using MQTTnet.Client.Receiving;
 using MQTTnet.Formatter;
+using MQTTnet.Packets;
 using MQTTnet.Protocol;
 using MQTTnet.Server;
 using MQTTnet.Tests.Mockups;
@@ -127,7 +124,13 @@ namespace MQTTnet.Tests.Server
                 var clientOptions = new MqttClientOptionsBuilder().WithWillMessage(willMessage);
 
                 var c1 = await testEnvironment.ConnectClient();
-                c1.ApplicationMessageReceivedHandler = new MqttApplicationMessageReceivedHandlerDelegate(c => Interlocked.Increment(ref receivedMessagesCount));
+                
+                c1.ApplicationMessageReceivedAsync +=  e =>
+                {
+                    Interlocked.Increment(ref receivedMessagesCount);
+                    return Task.CompletedTask;
+                };
+                
                 await c1.SubscribeAsync(new MqttTopicFilterBuilder().WithTopic("#").Build());
 
                 var c2 = await testEnvironment.ConnectClient(clientOptions);
@@ -150,7 +153,12 @@ namespace MQTTnet.Tests.Server
 
                 // C1 will receive the last will!
                 var c1 = await testEnvironment.ConnectClient();
-                c1.ApplicationMessageReceivedHandler = new MqttApplicationMessageReceivedHandlerDelegate(c => Interlocked.Increment(ref receivedMessagesCount));
+                c1.ApplicationMessageReceivedAsync += e =>
+                {
+                    Interlocked.Increment(ref receivedMessagesCount);
+                    return Task.CompletedTask;
+                };
+                
                 await c1.SubscribeAsync(new MqttTopicFilterBuilder().WithTopic("#").Build());
 
                 // C2 has the last will defined.
@@ -176,8 +184,6 @@ namespace MQTTnet.Tests.Server
         {
             using (var testEnvironment = CreateTestEnvironment())
             {
-                var receivedMessagesCount = 0;
-
                 await testEnvironment.StartServer();
 
                 var willMessage = new MqttApplicationMessageBuilder().WithTopic("My/last/will").WithAtMostOnceQoS().Build();
@@ -185,9 +191,19 @@ namespace MQTTnet.Tests.Server
                 var clientOptions = new MqttClientOptionsBuilder().WithWillMessage(willMessage);
 
                 var c1 = await testEnvironment.ConnectClient();
-                c1.UseApplicationMessageReceivedHandler(c => Interlocked.Increment(ref receivedMessagesCount));
+                
+                var receivedMessagesCount = 0;
+                c1.ApplicationMessageReceivedAsync += e =>
+                {
+                    Interlocked.Increment(ref receivedMessagesCount);
+                    return Task.CompletedTask;
+                };
+                
                 await c1.SubscribeAsync(new MqttTopicFilterBuilder().WithTopic("#").Build());
 
+                // clientOptions.WithClientId("Client2");
+                // var c2 = await testEnvironment.ConnectClient(clientOptions);
+
                 var c2 = await testEnvironment.ConnectClient(clientOptions);
                 c2.Dispose(); // Dispose will not send a DISCONNECT pattern first so the will message must be sent.
 
@@ -207,7 +223,11 @@ namespace MQTTnet.Tests.Server
                 var receivedMessagesCount = 0;
 
                 var client = await testEnvironment.ConnectClient();
-                client.UseApplicationMessageReceivedHandler(c => Interlocked.Increment(ref receivedMessagesCount));
+                client.ApplicationMessageReceivedAsync += e =>
+                {
+                    Interlocked.Increment(ref receivedMessagesCount);
+                    return Task.CompletedTask;
+                };
 
                 var message = new MqttApplicationMessageBuilder().WithTopic("a").WithAtLeastOnceQoS().Build();
                 await client.SubscribeAsync(new MqttTopicFilter {Topic = "a", QualityOfServiceLevel = MqttQualityOfServiceLevel.AtLeastOnce});
@@ -233,9 +253,17 @@ namespace MQTTnet.Tests.Server
                 var c2 = await testEnvironment.ConnectClient();
                 var c3 = await testEnvironment.ConnectClient();
 
-                c2.UseApplicationMessageReceivedHandler(c => { Interlocked.Increment(ref receivedMessagesCount); });
+                c2.ApplicationMessageReceivedAsync += e =>
+                {
+                    Interlocked.Increment(ref receivedMessagesCount);
+                    return Task.CompletedTask;
+                };
 
-                c3.UseApplicationMessageReceivedHandler(c => { Interlocked.Increment(ref receivedMessagesCount); });
+                c3.ApplicationMessageReceivedAsync += e =>
+                {
+                    Interlocked.Increment(ref receivedMessagesCount);
+                    return Task.CompletedTask;
+                };
 
                 await c2.SubscribeAsync(new MqttTopicFilter {Topic = "a", QualityOfServiceLevel = MqttQualityOfServiceLevel.AtLeastOnce}).ConfigureAwait(false);
                 await c3.SubscribeAsync(new MqttTopicFilter {Topic = "a", QualityOfServiceLevel = MqttQualityOfServiceLevel.AtLeastOnce}).ConfigureAwait(false);
@@ -293,13 +321,15 @@ namespace MQTTnet.Tests.Server
 
                 client.ConnectedHandler = new MqttClientConnectedHandlerDelegate(async e => { await client.PublishAsync("Connected"); });
 
-                client.UseApplicationMessageReceivedHandler(c =>
+                client.ApplicationMessageReceivedAsync += e =>
                 {
                     lock (receivedMessages)
                     {
-                        receivedMessages.Add(c.ApplicationMessage);
+                        receivedMessages.Add(e.ApplicationMessage);
                     }
-                });
+                    
+                    return Task.CompletedTask;
+                };
 
                 await Task.Delay(500);
 
@@ -327,13 +357,15 @@ namespace MQTTnet.Tests.Server
                 var client = await testEnvironment.ConnectClient();
                 var receivedMessages = new List<MqttApplicationMessage>();
 
-                client.UseApplicationMessageReceivedHandler(c =>
+                client.ApplicationMessageReceivedAsync += e =>
                 {
                     lock (receivedMessages)
                     {
-                        receivedMessages.Add(c.ApplicationMessage);
+                        receivedMessages.Add(e.ApplicationMessage);
                     }
-                });
+
+                    return Task.CompletedTask;
+                };
 
                 await Task.Delay(500);
 
@@ -511,7 +543,12 @@ namespace MQTTnet.Tests.Server
                 string receivedTopic = null;
                 var c1 = await testEnvironment.ConnectClient();
                 await c1.SubscribeAsync("#");
-                c1.UseApplicationMessageReceivedHandler(a => { receivedTopic = a.ApplicationMessage.Topic; });
+                
+                c1.ApplicationMessageReceivedAsync += a =>
+                {
+                    receivedTopic = a.ApplicationMessage.Topic;
+                    return Task.CompletedTask;
+                };
 
                 await c1.PublishAsync(new MqttApplicationMessageBuilder().WithTopic("original_topic").Build());
 
@@ -558,7 +595,12 @@ namespace MQTTnet.Tests.Server
                 string receivedTopic = null;
 
                 var c1 = await testEnvironment.ConnectClient();
-                c1.UseApplicationMessageReceivedHandler(e => { receivedTopic = e.ApplicationMessage.Topic; });
+                c1.ApplicationMessageReceivedAsync += e =>
+                {
+                    receivedTopic = e.ApplicationMessage.Topic;
+                    return Task.CompletedTask;
+                };
+                
                 await c1.SubscribeAsync("#");
 
                 await testEnvironment.ConnectClient();
@@ -589,10 +631,12 @@ namespace MQTTnet.Tests.Server
                 await c2.SubscribeAsync(new MqttTopicFilterBuilder().WithTopic("test").Build());
 
                 var isIntercepted = false;
-                c2.UseApplicationMessageReceivedHandler(c =>
+                c2.ApplicationMessageReceivedAsync += e =>
                 {
-                    isIntercepted = string.Compare("extended", Encoding.UTF8.GetString(c.ApplicationMessage.Payload), StringComparison.Ordinal) == 0;
-                });
+                    isIntercepted = string.Compare("extended", Encoding.UTF8.GetString(e.ApplicationMessage.Payload), StringComparison.Ordinal) == 0;
+                    
+                    return Task.CompletedTask;
+                };
 
                 await c1.PublishAsync(new MqttApplicationMessageBuilder().WithTopic("test").Build());
                 await c1.DisconnectAsync();
@@ -631,7 +675,11 @@ namespace MQTTnet.Tests.Server
                 await testEnvironment.StartServer();
 
                 var client1 = await testEnvironment.ConnectClient();
-                client1.UseApplicationMessageReceivedHandler(c => { receivedBody = c.ApplicationMessage.Payload; });
+                client1.ApplicationMessageReceivedAsync += e =>
+                {
+                    receivedBody = e.ApplicationMessage.Payload;
+                    return Task.CompletedTask;
+                };
 
                 await client1.SubscribeAsync("string");
 
@@ -732,13 +780,15 @@ namespace MQTTnet.Tests.Server
                 });
 
 
-                c1.UseApplicationMessageReceivedHandler(_ =>
+                c1.ApplicationMessageReceivedAsync += e =>
                 {
                     lock (events)
                     {
                         events.Add("r");
                     }
-                });
+
+                    return Task.CompletedTask;
+                };
 
                 c1.SubscribeAsync("topic").Wait();
 
@@ -825,13 +875,15 @@ namespace MQTTnet.Tests.Server
 
                 Assert.AreEqual("cdc", flow);
 
-                c2.UseApplicationMessageReceivedHandler(_ =>
+                c2.ApplicationMessageReceivedAsync += e =>
                 {
                     lock (events)
                     {
                         events.Add("r");
                     }
-                });
+                    
+                    return Task.CompletedTask;
+                };
 
                 await c2.SubscribeAsync("topic");
 
@@ -941,13 +993,15 @@ namespace MQTTnet.Tests.Server
 
                 var buffer = new StringBuilder();
 
-                client2.UseApplicationMessageReceivedHandler(c =>
+                client2.ApplicationMessageReceivedAsync += e =>
                 {
                     lock (buffer)
                     {
-                        buffer.Append(c.ApplicationMessage.Topic);
+                        buffer.Append(e.ApplicationMessage.Topic);
                     }
-                });
+                    
+                    return Task.CompletedTask;
+                };
 
                 await client2.SubscribeAsync(new MqttTopicFilter {Topic = "y"}, new MqttTopicFilter {Topic = "n"});
 
@@ -1016,7 +1070,7 @@ namespace MQTTnet.Tests.Server
                 await c1.UnsubscribeAsync(topicFilter);
                 await Task.Delay(500);
 
-                Assert.AreEqual(expectedReceivedMessagesCount, c1MessageHandler.ReceivedApplicationMessages.Count);
+                Assert.AreEqual(expectedReceivedMessagesCount, c1MessageHandler.ReceivedEventArgs.Count);
             }
         }
 

Tests/MQTTnet.Core.Tests/Server/MqttSubscriptionsManager_Tests.cs

@@ -5,7 +5,6 @@ using Microsoft.VisualStudio.TestTools.UnitTesting;
 using MQTTnet.Packets;
 using MQTTnet.Protocol;
 using MQTTnet.Server;
-using MQTTnet.Server.Internal;
 using MQTTnet.Tests.Mockups;
 
 namespace MQTTnet.Tests.Server
@@ -18,7 +17,7 @@ namespace MQTTnet.Tests.Server
         {
             var s = CreateSession();
 
-            var sm = new MqttClientSubscriptionsManager(s, new MqttServerOptions(), new MqttServerEventContainer(new TestLogger()), new MqttRetainedMessagesManager());
+            var sm = new MqttClientSubscriptionsManager(s, new MqttServerOptions(), new MqttServerEventContainer(), new MqttRetainedMessagesManager());
 
             var sp = new MqttSubscribePacket();
             sp.TopicFilters.Add(new MqttTopicFilterBuilder().WithTopic("A/B/C").Build());
@@ -35,7 +34,7 @@ namespace MQTTnet.Tests.Server
         {
             var s = CreateSession();
 
-            var sm = new MqttClientSubscriptionsManager(s, new MqttServerOptions(), new MqttServerEventContainer(new TestLogger()), new MqttRetainedMessagesManager());
+            var sm = new MqttClientSubscriptionsManager(s, new MqttServerOptions(), new MqttServerEventContainer(), new MqttRetainedMessagesManager());
 
             var sp = new MqttSubscribePacket();
             sp.TopicFilters.Add(new MqttTopicFilter { Topic = "A/B/C", QualityOfServiceLevel = MqttQualityOfServiceLevel.AtMostOnce });
@@ -52,7 +51,7 @@ namespace MQTTnet.Tests.Server
         {
             var s = CreateSession();
 
-            var sm = new MqttClientSubscriptionsManager(s, new MqttServerOptions(), new MqttServerEventContainer(new TestLogger()), new MqttRetainedMessagesManager());
+            var sm = new MqttClientSubscriptionsManager(s, new MqttServerOptions(), new MqttServerEventContainer(), new MqttRetainedMessagesManager());
 
             var sp = new MqttSubscribePacket();
             sp.TopicFilters.Add(new MqttTopicFilter { Topic = "#", QualityOfServiceLevel = MqttQualityOfServiceLevel.AtMostOnce });
@@ -70,7 +69,7 @@ namespace MQTTnet.Tests.Server
         {
             var s = CreateSession();
 
-            var sm = new MqttClientSubscriptionsManager(s, new MqttServerOptions(), new MqttServerEventContainer(new TestLogger()), new MqttRetainedMessagesManager());
+            var sm = new MqttClientSubscriptionsManager(s, new MqttServerOptions(), new MqttServerEventContainer(), new MqttRetainedMessagesManager());
 
             var sp = new MqttSubscribePacket();
             sp.TopicFilters.Add(new MqttTopicFilterBuilder().WithTopic("A/B/C").Build());
@@ -85,7 +84,7 @@ namespace MQTTnet.Tests.Server
         {
             var s = CreateSession();
 
-            var sm = new MqttClientSubscriptionsManager(s, new MqttServerOptions(), new MqttServerEventContainer(new TestLogger()), new MqttRetainedMessagesManager());
+            var sm = new MqttClientSubscriptionsManager(s, new MqttServerOptions(), new MqttServerEventContainer(), new MqttRetainedMessagesManager());
 
             var sp = new MqttSubscribePacket();
             sp.TopicFilters.Add(new MqttTopicFilterBuilder().WithTopic("A/B/C").Build());
@@ -106,7 +105,7 @@ namespace MQTTnet.Tests.Server
             var logger = new TestLogger();
             var options = new MqttServerOptions();
             var retainedMessagesManager = new MqttRetainedMessagesManager();
-            var eventContainer = new MqttServerEventContainer(logger);
+            var eventContainer = new MqttServerEventContainer();
                 
             return new MqttClientSession(
                 "",

Tests/MQTTnet.Core.Tests/Server/Retain_As_Published_Tests.cs

@@ -37,7 +37,7 @@ namespace MQTTnet.Tests.Server
                 await LongTestDelay();
 
                 applicationMessageHandler.AssertReceivedCountEquals(1);
-                Assert.AreEqual(retainAsPublished, applicationMessageHandler.ReceivedApplicationMessages[0].Retain);
+                Assert.AreEqual(retainAsPublished, applicationMessageHandler.ReceivedEventArgs[0].ApplicationMessage.Retain);
             }
         }
     }

Tests/MQTTnet.Core.Tests/Server/Retained_Messages_Tests.cs

@@ -3,6 +3,7 @@ using System.Threading.Tasks;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using MQTTnet.Client;
 using MQTTnet.Formatter;
+using MQTTnet.Packets;
 using MQTTnet.Protocol;
 
 namespace MQTTnet.Tests.Server
@@ -18,6 +19,7 @@ namespace MQTTnet.Tests.Server
                 await testEnvironment.StartServer();
 
                 var client = testEnvironment.CreateClient();
+                
                 var connectResult = await client.ConnectAsync(testEnvironment.Factory.CreateClientOptionsBuilder()
                     .WithProtocolVersion(MqttProtocolVersion.V311)
                     .WithTcpServer("127.0.0.1", testEnvironment.ServerPort).Build());
@@ -114,7 +116,7 @@ namespace MQTTnet.Tests.Server
                 await Task.Delay(500);
 
                 messageHandler.AssertReceivedCountEquals(1);
-                Assert.IsTrue(messageHandler.ReceivedApplicationMessages.First().Retain);
+                Assert.IsTrue(messageHandler.ReceivedEventArgs.First().ApplicationMessage.Retain);
             }
         }
 

Tests/MQTTnet.Core.Tests/Server/Security_Tests.cs

@@ -2,8 +2,6 @@
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using MQTTnet.Adapter;
 using MQTTnet.Client;
-using MQTTnet.Client.Connecting;
-using MQTTnet.Client.Options;
 using MQTTnet.Exceptions;
 using MQTTnet.Protocol;
 

Tests/MQTTnet.Core.Tests/Server/Server_Reference_Tests.cs

@@ -2,8 +2,6 @@
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using MQTTnet.Adapter;
 using MQTTnet.Client;
-using MQTTnet.Client.Connecting;
-using MQTTnet.Client.Options;
 using MQTTnet.Formatter;
 using MQTTnet.Protocol;
 

Tests/MQTTnet.Core.Tests/Server/Session_Tests.cs

@@ -4,9 +4,6 @@ using System.Text;
 using System.Threading.Tasks;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using MQTTnet.Client;
-using MQTTnet.Client.Options;
-using MQTTnet.Client.Publishing;
-using MQTTnet.Client.Subscribing;
 using MQTTnet.Protocol;
 using MQTTnet.Server;
 using MQTTnet.Tests.Mockups;
@@ -57,10 +54,11 @@ namespace MQTTnet.Tests.Server
                 string receivedPayload = null;
 
                 var client = await testEnvironment.ConnectClient();
-                client.UseApplicationMessageReceivedHandler(delegate(MqttApplicationMessageReceivedEventArgs args)
+                client.ApplicationMessageReceivedAsync += e =>
                 {
-                    receivedPayload = args.ApplicationMessage.ConvertPayloadToString();
-                });
+                    receivedPayload = e.ApplicationMessage.ConvertPayloadToString();
+                    return Task.CompletedTask;
+                };
 
                 var subscribeResult = await client.SubscribeAsync("x");
 
@@ -170,8 +168,8 @@ namespace MQTTnet.Tests.Server
                 await LongTestDelay();
                 
                 // Assert 
-                Assert.AreEqual(1, messageReceivedHandler.ReceivedApplicationMessages.Count);
-                Assert.AreEqual("injected_one", messageReceivedHandler.ReceivedApplicationMessages[0].Topic);
+                Assert.AreEqual(1, messageReceivedHandler.ReceivedEventArgs.Count);
+                Assert.AreEqual("injected_one", messageReceivedHandler.ReceivedEventArgs[0].ApplicationMessage.Topic);
             }
         }
         
@@ -191,13 +189,13 @@ namespace MQTTnet.Tests.Server
                     .WithClientId(qos.ToString())
                     .WithCleanSession(false));
                 
-                subscriber.UseApplicationMessageReceivedHandler(c =>
+                subscriber.ApplicationMessageReceivedAsync += c =>
                 {
                     c.AutoAcknowledge = false;
                     ++count;
                     Console.WriteLine("process");
                     return Task.CompletedTask;
-                });
+                };
                 
                 await subscriber.SubscribeAsync("#", qos);
 

Tests/MQTTnet.Core.Tests/Server/Shared_Subscriptions_Tests.cs

@@ -1,7 +1,6 @@
 using System.Threading.Tasks;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using MQTTnet.Client;
-using MQTTnet.Client.Subscribing;
 using MQTTnet.Formatter;
 
 namespace MQTTnet.Tests.Server

Tests/MQTTnet.Core.Tests/Server/Status_Tests.cs

@@ -2,7 +2,6 @@
 using System.Threading.Tasks;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using MQTTnet.Client;
-using MQTTnet.Client.Options;
 using MQTTnet.Protocol;
 using MQTTnet.Server;
 using MQTTnet.Tests.Mockups;
@@ -141,7 +140,8 @@ namespace MQTTnet.Tests.Server
                     // At most once will send one packet to the client and the server will reply
                     // with an additional ACK packet.
                     await c1.PublishAsync("a", string.Empty, MqttQualityOfServiceLevel.AtLeastOnce);
-                    await Task.Delay(250);
+                    
+                    await Task.Delay(500);
 
                     var clientStatus = await server.GetClientStatusAsync();
 
@@ -150,8 +150,8 @@ namespace MQTTnet.Tests.Server
                     // + 1 because CONNECT is also counted.
                     Assert.AreEqual(i + 1, clientStatus.First().SentPacketsCount, "SPC invalid!");
 
-                    // +1 because ConnACK package is already counted.
-                    Assert.AreEqual(i + 1, clientStatus.First().ReceivedPacketsCount, "RPC invalid!");
+                    // +2 because ConnACK + PubAck package is already counted.
+                    Assert.AreEqual(i + 2, clientStatus.First().ReceivedPacketsCount, "RPC invalid!");
                 }
             }
         }

Tests/MQTTnet.Core.Tests/Server/Subscribe_Tests.cs

@@ -3,9 +3,8 @@ using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using MQTTnet.Client;
-using MQTTnet.Client.Options;
-using MQTTnet.Client.Subscribing;
 using MQTTnet.Formatter;
+using MQTTnet.Packets;
 using MQTTnet.Protocol;
 using MQTTnet.Server;
 
@@ -33,17 +32,19 @@ namespace MQTTnet.Tests.Server
                 var topicBReceived = false;
 
                 var client = await testEnvironment.ConnectClient();
-                client.UseApplicationMessageReceivedHandler(c =>
+                client.ApplicationMessageReceivedAsync += e =>
                 {
-                    if (c.ApplicationMessage.Topic == "a")
+                    if (e.ApplicationMessage.Topic == "a")
                     {
                         topicAReceived = true;
                     }
-                    else if (c.ApplicationMessage.Topic == "b")
+                    else if (e.ApplicationMessage.Topic == "b")
                     {
                         topicBReceived = true;
                     }
-                });
+                    
+                    return Task.CompletedTask;
+                };
 
                 await client.SubscribeAsync("b");
 
@@ -66,7 +67,11 @@ namespace MQTTnet.Tests.Server
                 var server = await testEnvironment.StartServer();
 
                 var c1 = await testEnvironment.ConnectClient(new MqttClientOptionsBuilder().WithClientId("c1"));
-                c1.UseApplicationMessageReceivedHandler(c => Interlocked.Increment(ref receivedMessagesCount));
+                c1.ApplicationMessageReceivedAsync += e =>
+                {
+                    Interlocked.Increment(ref receivedMessagesCount);
+                    return Task.CompletedTask;
+                };
 
                 var c2 = await testEnvironment.ConnectClient(new MqttClientOptionsBuilder().WithClientId("c2"));
 
@@ -122,7 +127,12 @@ namespace MQTTnet.Tests.Server
                 await testEnvironment.StartServer();
 
                 var c1 = await testEnvironment.ConnectClient();
-                c1.UseApplicationMessageReceivedHandler(c => Interlocked.Increment(ref receivedMessagesCount));
+                c1.ApplicationMessageReceivedAsync += e =>
+                {
+                    Interlocked.Increment(ref receivedMessagesCount);
+                    return Task.CompletedTask;
+                };
+                
                 await c1.SubscribeAsync(new MqttClientSubscribeOptionsBuilder()
                     .WithTopicFilter("a")
                     .WithTopicFilter("b")
@@ -155,7 +165,11 @@ namespace MQTTnet.Tests.Server
                 await testEnvironment.StartServer();
 
                 var c1 = await testEnvironment.ConnectClient();
-                c1.UseApplicationMessageReceivedHandler(c => Interlocked.Increment(ref receivedMessagesCount));
+                c1.ApplicationMessageReceivedAsync += e =>
+                {
+                    Interlocked.Increment(ref receivedMessagesCount);
+                    return Task.CompletedTask;
+                };
 
                 var optionsBuilder = new MqttClientSubscribeOptionsBuilder();
                 for (var i = 0; i < 500; i++)
@@ -191,7 +205,11 @@ namespace MQTTnet.Tests.Server
                 await testEnvironment.StartServer();
 
                 var c1 = await testEnvironment.ConnectClient();
-                c1.UseApplicationMessageReceivedHandler(c => Interlocked.Increment(ref receivedMessagesCount));
+                c1.ApplicationMessageReceivedAsync += e =>
+                {
+                    Interlocked.Increment(ref receivedMessagesCount);
+                    return Task.CompletedTask;
+                };
 
                 for (var i = 0; i < 500; i++)
                 {
@@ -231,7 +249,12 @@ namespace MQTTnet.Tests.Server
                 await testEnvironment.StartServer();
 
                 var c1 = await testEnvironment.ConnectClient();
-                c1.UseApplicationMessageReceivedHandler(c => Interlocked.Increment(ref receivedMessagesCount));
+                c1.ApplicationMessageReceivedAsync += e =>
+                {
+                    Interlocked.Increment(ref receivedMessagesCount);
+                    return Task.CompletedTask;
+                };
+                
                 await c1.SubscribeAsync(new MqttClientSubscribeOptionsBuilder()
                     .WithTopicFilter("a")
                     .Build());

Tests/MQTTnet.Core.Tests/Server/Subscription_Identifier_Tests.cs

@@ -47,7 +47,7 @@ namespace MQTTnet.Tests.Server
 
                 applicationMessageHandler.AssertReceivedCountEquals(1);
 
-                applicationMessageHandler.ReceivedApplicationMessages[0].SubscriptionIdentifiers.Contains(456);
+                applicationMessageHandler.ReceivedEventArgs[0].ApplicationMessage.SubscriptionIdentifiers.Contains(456);
             }
         }
         
@@ -81,8 +81,8 @@ namespace MQTTnet.Tests.Server
 
                 applicationMessageHandler.AssertReceivedCountEquals(1);
 
-                applicationMessageHandler.ReceivedApplicationMessages[0].SubscriptionIdentifiers.Contains(456);
-                applicationMessageHandler.ReceivedApplicationMessages[0].SubscriptionIdentifiers.Contains(789);
+                applicationMessageHandler.ReceivedEventArgs[0].ApplicationMessage.SubscriptionIdentifiers.Contains(456);
+                applicationMessageHandler.ReceivedEventArgs[0].ApplicationMessage.SubscriptionIdentifiers.Contains(789);
             }
         }
     }

Tests/MQTTnet.Core.Tests/Server/TopicFilterComparer_Tests.cs

@@ -1,5 +1,5 @@
 using Microsoft.VisualStudio.TestTools.UnitTesting;
-using MQTTnet.Server.Internal;
+using MQTTnet.Server;
 
 namespace MQTTnet.Tests.Server
 {

Tests/MQTTnet.Core.Tests/Server/Topic_Alias_Tests.cs

@@ -3,7 +3,6 @@ using System.Linq;
 using System.Threading.Tasks;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using MQTTnet.Client;
-using MQTTnet.Client.Options;
 using MQTTnet.Formatter;
 
 namespace MQTTnet.Tests.Server
@@ -39,13 +38,15 @@ namespace MQTTnet.Tests.Server
                 var receivedTopics = new List<string>();
 
                 var c1 = await testEnvironment.ConnectClient(options => options.WithProtocolVersion(MqttProtocolVersion.V500));
-                c1.UseApplicationMessageReceivedHandler(e =>
+                c1.ApplicationMessageReceivedAsync += e =>
                 {
                     lock (receivedTopics)
                     {
                         receivedTopics.Add(e.ApplicationMessage.Topic);
                     }
-                });
+                    
+                    return Task.CompletedTask;
+                };
 
                 await c1.SubscribeAsync("#");
 

Tests/MQTTnet.Core.Tests/Server/User_Properties_Tests.cs

@@ -3,9 +3,8 @@ using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using MQTTnet.Client;
-using MQTTnet.Client.Options;
-using MQTTnet.Client.Subscribing;
 using MQTTnet.Formatter;
+using MQTTnet.Packets;
 using MQTTnet.Tests.Mockups;
 
 namespace MQTTnet.Tests.Server
@@ -41,7 +40,11 @@ namespace MQTTnet.Tests.Server
                 }, CancellationToken.None);
 
                 MqttApplicationMessage receivedMessage = null;
-                receiver.UseApplicationMessageReceivedHandler(e => receivedMessage = e.ApplicationMessage);
+                receiver.ApplicationMessageReceivedAsync += e =>
+                {
+                    receivedMessage = e.ApplicationMessage;
+                    return Task.CompletedTask;
+                };
 
                 await sender.PublishAsync(message.Build(), CancellationToken.None);