title: Socket.io socket.emit ack never runs
body: <p>From the docs, if you emit an event and pass a function, you should see the callback run.When I debug, this anonymous function never runs.</p>
  
  <pre><code>socket.emit('ferret', 'tobi', function (data) {
    console.log(data); // never called
  });
  </code></pre>
  
  <p>However</p>
  
  <pre><code>socket.on('ferret', function(data){
        console.log(data); // data 
  })
  socket.emit('ferret');
  </code></pre>
  
  <p>So the event listener works, but the emit callback does not..</p>