title: Socket.io Server-side callback
body: <p>I've successfully made a callback with <a href="http://socket.io" rel="nofollow">http://socket.io</a> when the client calls the server<br /></p>
  
  <pre><code>socket.on('event', function(data, fn){ fn(null, true); }
  </code></pre>
  
  <p>I was wondering if its possible to do the same but this time when the server calls the client?</p>