Remove not used timeout for receiving.

Source/MQTTnet.AspnetCore/MqttConnectionContext.cs

@@ -92,7 +92,7 @@ namespace MQTTnet.AspNetCore
             return Task.CompletedTask;
         }
 
-        public async Task<MqttBasePacket> ReceivePacketAsync(TimeSpan timeout, CancellationToken cancellationToken)
+        public async Task<MqttBasePacket> ReceivePacketAsync(CancellationToken cancellationToken)
         {
             var input = Connection.Transport.Input;
 

Source/MQTTnet/Adapter/IMqttChannelAdapter.cs

@@ -29,7 +29,7 @@ namespace MQTTnet.Adapter
 
         Task SendPacketAsync(MqttBasePacket packet, TimeSpan timeout, CancellationToken cancellationToken);
 
-        Task<MqttBasePacket> ReceivePacketAsync(TimeSpan timeout, CancellationToken cancellationToken);
+        Task<MqttBasePacket> ReceivePacketAsync(CancellationToken cancellationToken);
 
         void ResetStatistics();
     }

Source/MQTTnet/Adapter/MqttChannelAdapter.cs

@@ -155,42 +155,33 @@ namespace MQTTnet.Adapter
             }
         }
 
-        public async Task<MqttBasePacket> ReceivePacketAsync(TimeSpan timeout, CancellationToken cancellationToken)
+        public async Task<MqttBasePacket> ReceivePacketAsync(CancellationToken cancellationToken)
         {
             cancellationToken.ThrowIfCancellationRequested();
             ThrowIfDisposed();
 
             try
             {
-                ReceivedMqttPacket receivedMqttPacket;
-                if (timeout == TimeSpan.Zero)
-                {
-                    receivedMqttPacket = await ReceiveAsync(cancellationToken).ConfigureAwait(false);
-                }
-                else
-                {
-                    receivedMqttPacket = await MqttTaskTimeout.WaitAsync(ReceiveAsync, timeout, cancellationToken).ConfigureAwait(false);
-                }
-
-                if (receivedMqttPacket == null || cancellationToken.IsCancellationRequested)
+                var receivedPacket = await ReceiveAsync(cancellationToken).ConfigureAwait(false);
+                if (receivedPacket == null || cancellationToken.IsCancellationRequested)
                 {
                     return null;
                 }
 
-                Interlocked.Add(ref _bytesSent, receivedMqttPacket.TotalLength);
+                Interlocked.Add(ref _bytesSent, receivedPacket.TotalLength);
 
                 if (PacketFormatterAdapter.ProtocolVersion == MqttProtocolVersion.Unknown)
                 {
-                    PacketFormatterAdapter.DetectProtocolVersion(receivedMqttPacket);
+                    PacketFormatterAdapter.DetectProtocolVersion(receivedPacket);
                 }
 
-                var packet = PacketFormatterAdapter.Decode(receivedMqttPacket);
+                var packet = PacketFormatterAdapter.Decode(receivedPacket);
                 if (packet == null)
                 {
                     throw new MqttProtocolViolationException("Received malformed packet.");
                 }
 
-                _logger.Verbose("RX ({0} bytes) <<< {1}", receivedMqttPacket.TotalLength, packet);
+                _logger.Verbose("RX ({0} bytes) <<< {1}", receivedPacket.TotalLength, packet);
 
                 return packet;
             }

Source/MQTTnet/Client/MqttClient.cs

@@ -493,7 +493,7 @@ namespace MQTTnet.Client
 
                 while (!cancellationToken.IsCancellationRequested)
                 {
-                    var packet = await _adapter.ReceivePacketAsync(TimeSpan.Zero, cancellationToken).ConfigureAwait(false);
+                    var packet = await _adapter.ReceivePacketAsync(cancellationToken).ConfigureAwait(false);
 
                     if (cancellationToken.IsCancellationRequested)
                     {

Source/MQTTnet/LowLevelClient/LowLevelMqttClient.cs

@@ -18,10 +18,9 @@ namespace MQTTnet.LowLevelClient
 
         public LowLevelMqttClient(IMqttClientAdapterFactory clientAdapterFactory, IMqttNetLogger logger)
         {
-            if (clientAdapterFactory is null) throw new ArgumentNullException(nameof(clientAdapterFactory));
-            if (logger is null) throw new ArgumentNullException(nameof(logger));
+            _clientAdapterFactory = clientAdapterFactory ?? throw new ArgumentNullException(nameof(clientAdapterFactory));
 
-            _clientAdapterFactory = clientAdapterFactory;
+            if (logger is null) throw new ArgumentNullException(nameof(logger));
             _logger = logger.CreateScopedLogger(nameof(LowLevelMqttClient));
         }
 
@@ -95,7 +94,7 @@ namespace MQTTnet.LowLevelClient
 
             try
             {
-                return await _adapter.ReceivePacketAsync(_options.CommunicationTimeout, cancellationToken).ConfigureAwait(false);
+                return await _adapter.ReceivePacketAsync(cancellationToken).ConfigureAwait(false);
             }
             catch (Exception)
             {

Source/MQTTnet/Server/MqttClientConnection.cs

@@ -167,7 +167,7 @@ namespace MQTTnet.Server
                 {
                     Status = MqttClientConnectionStatus.Running;
 
-                    var packet = await _channelAdapter.ReceivePacketAsync(TimeSpan.Zero, cancellationToken).ConfigureAwait(false);
+                    var packet = await _channelAdapter.ReceivePacketAsync(cancellationToken).ConfigureAwait(false);
                     if (packet == null)
                     {
                         // The client has closed the connection gracefully.

Source/MQTTnet/Server/MqttClientSessionsManager.cs

@@ -12,6 +12,7 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
+using OperationCanceledException = System.OperationCanceledException;
 
 namespace MQTTnet.Server
 {
@@ -59,14 +60,24 @@ namespace MQTTnet.Server
                 MqttConnectPacket connectPacket;
                 try
                 {
-                    var firstPacket = await channelAdapter.ReceivePacketAsync(_options.DefaultCommunicationTimeout, cancellationToken).ConfigureAwait(false);
-                    connectPacket = firstPacket as MqttConnectPacket;
-                    if (connectPacket == null)
+                    using (var timeoutToken = new CancellationTokenSource(_options.DefaultCommunicationTimeout))
                     {
-                        _logger.Warning(null, "The first packet from client '{0}' was no 'CONNECT' packet [MQTT-3.1.0-1].", channelAdapter.Endpoint);
-                        return;
+                        var firstPacket = await channelAdapter.ReceivePacketAsync(timeoutToken.Token).ConfigureAwait(false);
+                        connectPacket = firstPacket as MqttConnectPacket;
+                        if (connectPacket == null)
+                        {
+                            _logger.Warning(null,
+                                "The first packet from client '{0}' was no 'CONNECT' packet [MQTT-3.1.0-1].",
+                                channelAdapter.Endpoint);
+                            return;
+                        }
                     }
                 }
+                catch (OperationCanceledException)
+                {
+                    _logger.Warning(null, "Client '{0}' connected but did not sent a CONNECT packet.", channelAdapter.Endpoint);
+                    return;
+                }
                 catch (MqttCommunicationTimedOutException)
                 {
                     _logger.Warning(null, "Client '{0}' connected but did not sent a CONNECT packet.", channelAdapter.Endpoint);

Source/MQTTnet/Server/MqttServerKeepAliveMonitor.cs

@@ -105,7 +105,10 @@ namespace MQTTnet.Server
 
                 // Execute the disconnection in background so that the keep alive monitor can continue
                 // with checking other connections.
-                Task.Run(() => connection.StopAsync(MqttDisconnectReasonCode.KeepAliveTimeout));
+                // We do not need to wait for the task so no await is needed.
+                // Also the internal state of the connection must be swapped to "Finalizing" because the
+                // next iteration of the keep alive timer happens.
+                var _ = connection.StopAsync(MqttDisconnectReasonCode.KeepAliveTimeout);
             }
             catch (Exception exception)
             {