title: Socket.io emit callback not firing on server side?
body: <p>My server emits events properly, but the emit callback never works.  In the following, nothing is logged on my console:</p>
  
  <p>Server:</p>
  
  <pre><code>io.sockets.emit('delete hint', {id: id}, function(data){
                      console.log('callback');
                  });
  </code></pre>
  
  <p>Client:</p>
  
  <pre><code>socket.on('delete hint', function(data){
      // display a message before deleting
      $('#' + data.id).fadeOut(function(){ 
          $(this).remove();
      });
  });
  </code></pre>
  
  <p>I've also tried the client side code as function(data, fn) in case the callback needed to be included on the receiving function. </p>
  
  <p>I'm using windows and my command prompt shows the following when socket.io is emitting the event:</p>
  
  <pre><code>websocket writing 5:::{"name":"delete hint", "args":[{"id":"1"}, null]}
  </code></pre>
  
  <p>I can't figure out what the problem is, what am I doing wrong?</p>