event is triggered but something is blocking

Source/MQTTnet/Implementations/MqttTcpChannel.cs

@@ -87,8 +87,14 @@ namespace MQTTnet.Implementations
 
         public void Dispose()
         {
-            TryDispose(_stream, () => _stream = null);
-            TryDispose(_socket, () => _socket = null);
+            Cleanup(ref _stream, (s) => s.Dispose());
+            Cleanup(ref _socket, (s) => {
+                if (s.Connected)
+                {
+                    s.Shutdown(SocketShutdown.Both);
+                }
+                s.Dispose();
+            });
         }
 
         private bool InternalUserCertificateValidationCallback(object sender, X509Certificate x509Certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)
@@ -157,11 +163,16 @@ namespace MQTTnet.Implementations
             }
         }
 
-        private static void TryDispose(IDisposable disposable, Action afterDispose)
+        private static void Cleanup<T>(ref T item, Action<T> handler) where T : class
         {
+            var temp = item;
+            item = null;
             try
             {
-                disposable?.Dispose();
+                if (temp != null)
+                {
+                    handler(temp);
+                }
             }
             catch (ObjectDisposedException)
             {
@@ -169,10 +180,6 @@ namespace MQTTnet.Implementations
             catch (NullReferenceException)
             {
             }
-            finally
-            {
-                afterDispose();
-            }
         }
     }
 }