Fix issue when stopping server

Frameworks/MQTTnet.NetFramework/Implementations/MqttServerAdapter.cs

@@ -63,6 +63,7 @@ namespace MQTTnet.Implementations
         {
             _isRunning = false;
 
+            _cancellationTokenSource?.Cancel(false);
             _cancellationTokenSource?.Dispose();
             _cancellationTokenSource = null;
 
@@ -88,7 +89,7 @@ namespace MQTTnet.Implementations
                     var clientAdapter = new MqttChannelCommunicationAdapter(new MqttTcpChannel(clientSocket, null), new DefaultMqttV311PacketSerializer());
                     ClientConnected?.Invoke(this, new MqttClientConnectedEventArgs(clientSocket.RemoteEndPoint.ToString(), clientAdapter));
                 }
-                catch (Exception exception)
+                catch (Exception exception) when (!(exception is ObjectDisposedException))
                 {
                     MqttTrace.Error(nameof(MqttServerAdapter), exception, "Error while acceping connection at default endpoint.");
                 }

Frameworks/MQTTnet.NetStandard/Implementations/MqttServerAdapter.cs

@@ -61,6 +61,7 @@ namespace MQTTnet.Implementations
         {
             _isRunning = false;
 
+            _cancellationTokenSource?.Cancel(false);
             _cancellationTokenSource?.Dispose();
             _cancellationTokenSource = null;
 

MQTTnet.Core/Client/MqttClient.cs

@@ -185,7 +185,10 @@ namespace MQTTnet.Core.Client
             }
             finally
             {
-                _cancellationTokenSource?.Cancel();
+                _cancellationTokenSource?.Cancel(false);
+                _cancellationTokenSource?.Dispose();
+                _cancellationTokenSource = null;
+
                 IsConnected = false;
                 Disconnected?.Invoke(this, EventArgs.Empty);
             }

MQTTnet.Core/Server/MqttServer.cs

@@ -59,7 +59,8 @@ namespace MQTTnet.Core.Server
 
         public void Stop()
         {
-            _cancellationTokenSource?.Cancel();
+            _cancellationTokenSource?.Cancel(false);
+            _cancellationTokenSource?.Dispose();
             _cancellationTokenSource = null;
 
             foreach (var adapter in _adapters)