title: mqttnet client not getting subscribed topics
body: <p>I'm using mqtt.net (<a href="https://github.com/chkr1011/MQTTnet" rel="nofollow noreferrer">https://github.com/chkr1011/MQTTnet</a>) and have written a small class to handle my mqtt client. The client connects to the broker and publishes it's messages successfully. Now I want the client to also react on some topics I subscribe the client to. But this does not seem to work. I do not get any breakpoint hit. This are the relevant parts of my code:</p>
  
  <pre><code>    public async Task StartAsync(CancellationToken cancellationToken)
              {
          //Building the mqtt config
          var options = new MqttClientOptionsBuilder()
              .WithTcpServer(MqttConfig.Server, MqttConfig.Port)
              .WithClientId("HeaterService")
              .WithCredentials(MqttConfig.User, MqttConfig.Password)
              .WithTls(tlsParameters =&gt;
              {
                  tlsParameters.AllowUntrustedCertificates = true;
              })
              .WithCleanSession()
              .Build();
  
          //Getting an mqtt Instance
          MqttClient = new MqttFactory().CreateMqttClient();
  
          //Wiring up all the events...
          MqttClient.UseApplicationMessageReceivedHandler( e =&gt; { HandleMessageReceived(e.ApplicationMessage); });
  
          MqttClient.UseConnectedHandler(/*async*/ e =&gt;
          {
              Console.WriteLine("### CONNECTED WITH BROKER ###");
  
          });
  
        await MqttClient.ConnectAsync(options);
  }
  </code></pre>
  
  <p>The client connects successfully to the server and is possible to publish messages.</p>
  
  <p>This is my messagehandler function:</p>
  
  <pre><code>private void HandleMessageReceived(MqttApplicationMessage applicationMessage)
  {
      Console.WriteLine("### RECEIVED APPLICATION MESSAGE ###");
      Console.WriteLine($"+ Topic = {applicationMessage.Topic}");
  
      Console.WriteLine($"+ Payload = {Encoding.UTF8.GetString(applicationMessage.Payload)}");
      Console.WriteLine($"+ QoS = {applicationMessage.QualityOfServiceLevel}");
      Console.WriteLine($"+ Retain = {applicationMessage.Retain}");
      Console.WriteLine();
  }
  </code></pre>
  
  <p>This is my subscribe code:</p>
  
  <pre><code>public async Task SubscribeTopic(string topic)
  {
     var subscribeResult = await MqttClient.SubscribeAsync(new TopicFilterBuilder()
        .WithTopic(topic)
        //.WithQualityOfServiceLevel(MqttQualityOfServiceLevel.AtLeastOnce)
        .Build());
  
     Console.WriteLine("### SUBSCRIBED ###");
     Console.WriteLine("### Result: " + subscribeResult.Items.FirstOrDefault()?.ResultCode);
     Console.WriteLine("### Result: " + subscribeResult.Items.FirstOrDefault()?.TopicFilter);
  }
  </code></pre>
  
  <p>I call this function of my class with "Home/Heater/control/*";</p>
  
  <p>When I use mqtt-explorer to send a test message to the topic "Home/Heater/control/test" </p>
  
  <p>the functionhandler HandleMessageReceived is never hit.</p>
  
  <p>What I am doing wrong?</p>