From 3b02a5f6aab174aa8e6a9802c4703a57b86b8d38 Mon Sep 17 00:00:00 2001
From: Christian <christian.kratky@googlemail.com>
Date: Sat, 23 Feb 2019 10:40:17 +0100
Subject: [PATCH] Fix NullRefException when cancelling the server.

---
 Source/MQTTnet/Server/MqttClientSessionsManager.cs | 5 +++++
 Tests/MQTTnet.Core.Tests/MqttFactoryTests.cs       | 2 --
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/Source/MQTTnet/Server/MqttClientSessionsManager.cs b/Source/MQTTnet/Server/MqttClientSessionsManager.cs
index cf58ec7c..e0ce7e4e 100644
--- a/Source/MQTTnet/Server/MqttClientSessionsManager.cs
+++ b/Source/MQTTnet/Server/MqttClientSessionsManager.cs
@@ -170,6 +170,11 @@ namespace MQTTnet.Server
         {
             try
             {
+                if (cancellationToken.IsCancellationRequested)
+                {
+                    return;
+                }
+
                 var enqueuedApplicationMessage = _messageQueue.Take(cancellationToken);
 
                 var sender = enqueuedApplicationMessage.Sender;
diff --git a/Tests/MQTTnet.Core.Tests/MqttFactoryTests.cs b/Tests/MQTTnet.Core.Tests/MqttFactoryTests.cs
index 42f735fa..3bdaa05d 100644
--- a/Tests/MQTTnet.Core.Tests/MqttFactoryTests.cs
+++ b/Tests/MQTTnet.Core.Tests/MqttFactoryTests.cs
@@ -2,8 +2,6 @@
 using MQTTnet.Diagnostics;
 using MQTTnet.Extensions.ManagedClient;
 using System;
-using System.Collections.Generic;
-using System.Text;
 using System.Threading;
 using System.Threading.Tasks;