title: Sending instructions to a thread which is waiting for TCP?
body: <p>I'm trying to understand multi-threading in TCP so I'm coding a basic telnet text "router".</p>
  
  <p>using <code>ReadLine()</code> each thread using a TCP listener will wait for input from the telnet client and then respond based on the text which is sent. I have this working with multiple threads and multiple telnet clients.</p>
  
  <p>I want to conditionally send messages to all threads.
  For example, if the text sent from any one thread is "Alert!" then I want every thread for connected clients to execute <code>WriteLine("Alert!")</code></p>
  
  <p>Does this make sense?
  My problem is that I don't know how to make one thread raise an event in another thread.</p>