Refactor naming for background tasks.

Source/MQTTnet/Client/MqttClient.cs

@@ -355,7 +355,7 @@ namespace MQTTnet.Client
                 {
                     // This handler must be executed in a new thread because otherwise a dead lock may happen
                     // when trying to reconnect in that handler etc.
-                    Task.Run(() => disconnectedHandler.HandleDisconnectedAsync(new MqttClientDisconnectedEventArgs(clientWasConnected, exception, authenticateResult, _disconnectReason))).Forget(_logger);
+                    Task.Run(() => disconnectedHandler.HandleDisconnectedAsync(new MqttClientDisconnectedEventArgs(clientWasConnected, exception, authenticateResult, _disconnectReason))).RunInBackground(_logger);
                 }
             }
         }

Source/MQTTnet/Implementations/MqttTcpServerListener.cs

@@ -78,7 +78,7 @@ namespace MQTTnet.Implementations
                 _socket.Bind(_localEndPoint);
                 _socket.Listen(_options.ConnectionBacklog);
                 
-                Task.Run(() => AcceptClientConnectionsAsync(cancellationToken), cancellationToken).Forget(_logger);
+                Task.Run(() => AcceptClientConnectionsAsync(cancellationToken), cancellationToken).RunInBackground(_logger);
 
                 return true;
             }
@@ -115,7 +115,7 @@ namespace MQTTnet.Implementations
                         continue;
                     }
 
-                    Task.Run(() => TryHandleClientConnectionAsync(clientSocket), cancellationToken).Forget(_logger);
+                    Task.Run(() => TryHandleClientConnectionAsync(clientSocket), cancellationToken).RunInBackground(_logger);
                 }
                 catch (OperationCanceledException)
                 {

Source/MQTTnet/Internal/TaskExtensions.cs

@@ -5,11 +5,13 @@ namespace MQTTnet.Internal
 {
     public static class TaskExtensions
     {
-        public static void Forget(this Task task, IMqttNetScopedLogger logger)
+        public static void RunInBackground(this Task task, IMqttNetScopedLogger logger = null)
         {
             task?.ContinueWith(t =>
                 {
-                    logger.Error(t.Exception, "Unhandled exception.");
+                    // Consume the exception first so that we get no exception regarding the not observed exception.
+                    var exception = t.Exception;
+                    logger?.Error(exception, "Unhandled exception in background task.");
                 },
                 TaskContinuationOptions.OnlyOnFaulted);
         }

Source/MQTTnet/Server/MqttClientConnection.cs

@@ -160,7 +160,7 @@ namespace MQTTnet.Server
 
                 await SendAsync(_channelAdapter.PacketFormatterAdapter.DataConverter.CreateConnAckPacket(_connectionValidatorContext), cancellationToken).ConfigureAwait(false);
 
-                Task.Run(() => SendPendingPacketsAsync(cancellationToken), cancellationToken).Forget(_logger);
+                Task.Run(() => SendPendingPacketsAsync(cancellationToken), cancellationToken).RunInBackground(_logger);
 
                 Session.IsCleanSession = false;
 

Source/MQTTnet/Server/MqttClientSessionsManager.cs

@@ -50,7 +50,7 @@ namespace MQTTnet.Server
 
         public void Start(CancellationToken cancellationToken)
         {
-            Task.Run(() => TryProcessQueuedApplicationMessagesAsync(cancellationToken), cancellationToken).Forget(_logger);
+            Task.Run(() => TryProcessQueuedApplicationMessagesAsync(cancellationToken), cancellationToken).RunInBackground(_logger);
         }
 
         public async Task HandleClientConnectionAsync(IMqttChannelAdapter channelAdapter, CancellationToken cancellationToken)

Source/MQTTnet/Server/MqttServerKeepAliveMonitor.cs

@@ -29,7 +29,7 @@ namespace MQTTnet.Server
             // support async/await. Async etc. is avoided here because the thread will usually check
             // the connections every few milliseconds and thus the context changes (due to async) are 
             // only consuming resources. Also there is just 1 thread for the entire server which is fine at all!
-            Task.Factory.StartNew(_ => DoWork(cancellationToken), cancellationToken, TaskCreationOptions.LongRunning).Forget(_logger);
+            Task.Factory.StartNew(_ => DoWork(cancellationToken), cancellationToken, TaskCreationOptions.LongRunning).RunInBackground(_logger);
         }
 
         void DoWork(CancellationToken cancellationToken)