title: How to subscribe to multiple topics in C# mqttnet
body: <p>var topic3 = new TopicFilterBuilder().WithTopic(&quot;test&quot;).Build();
  Client.SubscribeAsync(topic3).Wait();</p>
  <pre><code>        Client.UseApplicationMessageReceivedHandler(e =&gt;
          {
  
              textBox1.Invoke(new Action(() =&gt;
              {
                  textBox1.Text = Encoding.UTF8.GetString(e.ApplicationMessage.Payload).ToString();
              }));
  
  
          });
  </code></pre>