title: Simple Telnet console that listens and accepts connections
body: <p>I am new to Telnet and C# and  I am trying to create a simple console program. I need a TCP listener that starts up, listens for incoming networking connections and sends a response back. I don’t really care for the incoming message but I need to accept it so the client thinks that the connection was successful. This TCP listener will respond with “Hello”. 
  I just need to make sure that it starts up cleanly and close the TCP listener gracefully without throwing any exceptions. I need to use “Telnet localhost 9090” to connect to the TCP listener on your laptop on port 9090.</p>
  
  <p>Can you help?</p>