title: NetMQ Request/Response sometimes fails when reopen the response server
body: <p>I am trying to use NetMQ to send and receive messages from the Request/Response pattern.
  I want to simulate network disconnect by reopen the response server.
  The messaging sometimes fails when reopen the response server.</p>
  <p>What am I doing wrong? Any information or assistance would be greatly appreciated.</p>
  <p>Request Client:</p>
  <pre><code>RequestSocket client = new RequestSocket();
  client.Connect(address);
  while(true)
  {
      client.SendFrame(dataBytes);
      client.ReceiveFrameString();
      Thread.Sleep(100);
  }
  </code></pre>
  <p>Also tried Request Client with Try*, and re-connect if the client does not receive any reponse for a while:</p>
  <pre><code>bool success = false;
  while(true)
  {
      success = client.TrySendFrame(TimeSpan.FromMilliseconds(500), dataBytes);
      if (success)
      {
          break;
      }
      Thread.Sleep(100);
  }
  
  int count = 0;
  success = false;
  while(true)
  {
      success = client.TryReceiveFrameString(TimeSpan.FromMilliseconds(500), out string s);
      if (success)
      {
          break;
      }
      count++;
      if (count &gt;= 50)
      {
          client.Disconnect(address);
          client.Connect(address);
          break;
      }
      Thread.Sleep(100);
  }
  </code></pre>
  <p>Response Server (manually close and open program again):</p>
  <pre><code>ResponseSocket server = new ResponseSocket(connection);
  while(true)
  {
      if (server.TryReceiveFrameBytes(TimeSpan.FromMilliseconds(300), out byte[] dataBytes))
      {
          server.SendFrame(&quot;Response&quot;);
      }
      Thread.Sleep(100);
  }
  </code></pre>