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

# Conflicts:
#	MQTTnet.Core/Serializer/MqttPacketReader.cs
#	MQTTnet.Core/Serializer/MqttPacketSerializer.cs
#	Tests/MQTTnet.TestApp.NetFramework/PerformanceTest.cs

MQTTnet.Core/Server/MqttClientMessageQueue.cs

@@ -1,20 +1,17 @@
 using System;
-using System.Collections.Generic;
-using System.Linq;
+using System.Collections.Concurrent;
 using System.Threading;
 using System.Threading.Tasks;
 using MQTTnet.Core.Adapter;
 using MQTTnet.Core.Diagnostics;
 using MQTTnet.Core.Exceptions;
-using MQTTnet.Core.Internal;
 using MQTTnet.Core.Packets;
 
 namespace MQTTnet.Core.Server
 {
     public sealed class MqttClientMessageQueue
     {
-        private readonly List<MqttClientPublishPacketContext> _pendingPublishPackets = new List<MqttClientPublishPacketContext>();
-        private readonly AsyncGate _gate = new AsyncGate();
+        private readonly BlockingCollection<MqttClientPublishPacketContext> _pendingPublishPackets = new BlockingCollection<MqttClientPublishPacketContext>();
 
         private readonly MqttServerOptions _options;
         private CancellationTokenSource _cancellationTokenSource;
@@ -43,26 +40,22 @@ namespace MQTTnet.Core.Server
             _adapter = null;
             _cancellationTokenSource?.Cancel();
             _cancellationTokenSource = null;
+            _pendingPublishPackets?.Dispose();
         }
 
         public void Enqueue(MqttPublishPacket publishPacket)
         {
             if (publishPacket == null) throw new ArgumentNullException(nameof(publishPacket));
 
-            lock (_pendingPublishPackets)
-            {
-                _pendingPublishPackets.Add(new MqttClientPublishPacketContext(publishPacket));
-                _gate.Set();
-            }
+            _pendingPublishPackets.Add(new MqttClientPublishPacketContext(publishPacket));
         }
 
         private async Task SendPendingPublishPacketsAsync(CancellationToken cancellationToken)
         {
-            while (!cancellationToken.IsCancellationRequested)
+            foreach (var publishPacket in _pendingPublishPackets.GetConsumingEnumerable(cancellationToken))
             {
                 try
                 {
-                    await _gate.WaitOneAsync().ConfigureAwait(false);
                     if (cancellationToken.IsCancellationRequested)
                     {
                         return;
@@ -73,25 +66,12 @@ namespace MQTTnet.Core.Server
                         continue;
                     }
 
-                    List<MqttClientPublishPacketContext> pendingPublishPackets;
-                    lock (_pendingPublishPackets)
-                    {
-                        pendingPublishPackets = _pendingPublishPackets.ToList();
-                    }
-
-                    foreach (var publishPacket in pendingPublishPackets)
-                    {
-                        await TrySendPendingPublishPacketAsync(publishPacket).ConfigureAwait(false);
-                    }
+                    await TrySendPendingPublishPacketAsync(publishPacket).ConfigureAwait(false);
                 }
                 catch (Exception e)
                 {
                     MqttTrace.Error(nameof(MqttClientMessageQueue), e, "Error while sending pending publish packets.");
                 }
-                finally
-                {
-                    Cleanup();
-                }               
             }
         }
 
@@ -105,30 +85,24 @@ namespace MQTTnet.Core.Server
                 }
 
                 publishPacketContext.PublishPacket.Dup = publishPacketContext.SendTries > 0;
-                await _adapter.SendPacketAsync(publishPacketContext.PublishPacket, _options.DefaultCommunicationTimeout).ConfigureAwait(false);
+                await _adapter.SendPacketsAsync(_options.DefaultCommunicationTimeout, publishPacketContext.PublishPacket).ConfigureAwait(false);
 
                 publishPacketContext.IsSent = true;
             }
             catch (MqttCommunicationException exception)
             {
                 MqttTrace.Warning(nameof(MqttClientMessageQueue), exception, "Sending publish packet failed.");
+                _pendingPublishPackets.Add(publishPacketContext);
             }
             catch (Exception exception)
             {
                 MqttTrace.Error(nameof(MqttClientMessageQueue), exception, "Sending publish packet failed.");
+                _pendingPublishPackets.Add(publishPacketContext);
             }
             finally
             {
                 publishPacketContext.SendTries++;
             }
         }
-
-        private void Cleanup()
-        {
-            lock (_pendingPublishPackets)
-            {
-                _pendingPublishPackets.RemoveAll(p => p.IsSent);
-            }
-        }
     }
 }

MQTTnet.Core/Server/MqttClientSession.cs

@@ -103,12 +103,12 @@ namespace MQTTnet.Core.Server
         {
             if (packet is MqttSubscribePacket subscribePacket)
             {
-                return Adapter.SendPacketAsync(_subscriptionsManager.Subscribe(subscribePacket), _options.DefaultCommunicationTimeout);
+                return Adapter.SendPacketsAsync(_options.DefaultCommunicationTimeout, _subscriptionsManager.Subscribe(subscribePacket));
             }
 
             if (packet is MqttUnsubscribePacket unsubscribePacket)
             {
-                return Adapter.SendPacketAsync(_subscriptionsManager.Unsubscribe(unsubscribePacket), _options.DefaultCommunicationTimeout);
+                return Adapter.SendPacketsAsync(_options.DefaultCommunicationTimeout, _subscriptionsManager.Unsubscribe(unsubscribePacket));
             }
 
             if (packet is MqttPublishPacket publishPacket)
@@ -123,7 +123,7 @@ namespace MQTTnet.Core.Server
 
             if (packet is MqttPubRecPacket pubRecPacket)
             {
-                return Adapter.SendPacketAsync(pubRecPacket.CreateResponse<MqttPubRelPacket>(), _options.DefaultCommunicationTimeout);
+                return Adapter.SendPacketsAsync(_options.DefaultCommunicationTimeout, pubRecPacket.CreateResponse<MqttPubRelPacket>());
             }
 
             if (packet is MqttPubAckPacket || packet is MqttPubCompPacket)
@@ -134,7 +134,7 @@ namespace MQTTnet.Core.Server
 
             if (packet is MqttPingReqPacket)
             {
-                return Adapter.SendPacketAsync(new MqttPingRespPacket(), _options.DefaultCommunicationTimeout);
+                return Adapter.SendPacketsAsync(_options.DefaultCommunicationTimeout, new MqttPingRespPacket());
             }
 
             if (packet is MqttDisconnectPacket || packet is MqttConnectPacket)
@@ -160,7 +160,7 @@ namespace MQTTnet.Core.Server
             if (publishPacket.QualityOfServiceLevel == MqttQualityOfServiceLevel.AtLeastOnce)
             {
                 _publishPacketReceivedCallback(this, publishPacket);
-                return Adapter.SendPacketAsync(new MqttPubAckPacket { PacketIdentifier = publishPacket.PacketIdentifier }, _options.DefaultCommunicationTimeout);
+                return Adapter.SendPacketsAsync(_options.DefaultCommunicationTimeout, new MqttPubAckPacket { PacketIdentifier = publishPacket.PacketIdentifier });
             }
 
             if (publishPacket.QualityOfServiceLevel == MqttQualityOfServiceLevel.ExactlyOnce)
@@ -173,7 +173,7 @@ namespace MQTTnet.Core.Server
 
                 _publishPacketReceivedCallback(this, publishPacket);
 
-                return Adapter.SendPacketAsync(new MqttPubRecPacket { PacketIdentifier = publishPacket.PacketIdentifier }, _options.DefaultCommunicationTimeout);
+                return Adapter.SendPacketsAsync(_options.DefaultCommunicationTimeout, new MqttPubRecPacket { PacketIdentifier = publishPacket.PacketIdentifier });
             }
 
             throw new MqttCommunicationException("Received a not supported QoS level.");
@@ -186,7 +186,7 @@ namespace MQTTnet.Core.Server
                 _unacknowledgedPublishPackets.Remove(pubRelPacket.PacketIdentifier);
             }
 
-            return Adapter.SendPacketAsync(new MqttPubCompPacket { PacketIdentifier = pubRelPacket.PacketIdentifier }, _options.DefaultCommunicationTimeout);
+            return Adapter.SendPacketsAsync(_options.DefaultCommunicationTimeout, new MqttPubCompPacket { PacketIdentifier = pubRelPacket.PacketIdentifier });
         }
     }
 }

MQTTnet.Core/Server/MqttClientSessionsManager.cs

@@ -40,21 +40,21 @@ namespace MQTTnet.Core.Server
                 var connectReturnCode = ValidateConnection(connectPacket);
                 if (connectReturnCode != MqttConnectReturnCode.ConnectionAccepted)
                 {
-                    await eventArgs.ClientAdapter.SendPacketAsync(new MqttConnAckPacket
+                    await eventArgs.ClientAdapter.SendPacketsAsync(_options.DefaultCommunicationTimeout, new MqttConnAckPacket
                     {
                         ConnectReturnCode = connectReturnCode
-                    }, _options.DefaultCommunicationTimeout).ConfigureAwait(false);
+                    }).ConfigureAwait(false);
 
                     return;
                 }
 
                 var clientSession = GetOrCreateClientSession(connectPacket);
 
-                await eventArgs.ClientAdapter.SendPacketAsync(new MqttConnAckPacket
+                await eventArgs.ClientAdapter.SendPacketsAsync(_options.DefaultCommunicationTimeout, new MqttConnAckPacket
                 {
                     ConnectReturnCode = connectReturnCode,
                     IsSessionPresent = clientSession.IsExistingSession
-                }, _options.DefaultCommunicationTimeout).ConfigureAwait(false);
+                }).ConfigureAwait(false);
 
                 await clientSession.Session.RunAsync(eventArgs.Identifier, connectPacket.WillMessage, eventArgs.ClientAdapter).ConfigureAwait(false);
             }

MQTTnet.Core/Server/MqttServer.cs

@@ -20,7 +20,7 @@ namespace MQTTnet.Core.Server
         {
             _options = options ?? throw new ArgumentNullException(nameof(options));
             _adapters = adapters ?? throw new ArgumentNullException(nameof(adapters));
-            
+
             _clientSessionsManager = new MqttClientSessionsManager(options);
             _clientSessionsManager.ApplicationMessageReceived += (s, e) => ApplicationMessageReceived?.Invoke(s, e);
         }
@@ -61,7 +61,7 @@ namespace MQTTnet.Core.Server
                 adapter.ClientConnected += OnClientConnected;
                 adapter.Start(_options);
             }
-            
+
             MqttTrace.Information(nameof(MqttServer), "Started.");
         }
 

MQTTnet.Core/Server/MqttServerOptions.cs

@@ -9,7 +9,7 @@ namespace MQTTnet.Core.Server
         public MqttServerDefaultEndpointOptions DefaultEndpointOptions { get; } = new MqttServerDefaultEndpointOptions();
 
         public MqttServerTlsEndpointOptions TlsEndpointOptions { get; } = new MqttServerTlsEndpointOptions();
-        
+
         public int ConnectionBacklog { get; set; } = 10;
 
         public TimeSpan DefaultCommunicationTimeout { get; set; } = TimeSpan.FromSeconds(15);