title: SocketIO disconnects as transport close when is a ping timeout
body: <p>I am using socket.io version 2.0.4, for both nodejs and the client, and have the following code for the internal ping function socketio uses:</p>
  
  <p><code>var io = require('socket.io').listen(app, {'pingInterval': 5000, 'pingTimeout': 10000});</code></p>
  
  <p>My problem is that when my client loses connection on the socket disconnect event sometimes it tells me that is due to transport close instead of ping timeout.</p>
  
  <pre><code> socket.on('disconnect', function(reason) {
      console.log(reason)});
  </code></pre>
  
  <p>Is there anything that may cause my server think the user has close its connection?</p>