title: socket.io: Disconnect event - 'transport close', 'client namespace disconnect', 'transport error' and 'forced close'
body: <p>Using socket.io v1.2.1 (only using the "polling" transport), sometimes my clients experience disconnections.</p>
  
  <p>About 50% of the time I get <code>ping timeout</code> on my disconnect event callback function, which is reasonable.</p>
  
  <p>Other times, I get <code>transport close</code>, <code>client namespace disconnect</code>, <code>transport error</code> and <code>forced close</code>. I did not find any reference to those disconnection reasons in the documentation, and was not able to really understand their meaning from the code.</p>
  
  <p>I want to make sure I handle each disconnection the best way (and maybe prevent them).</p>
  
  <p>Maybe someone can shed a little light about these reasons.</p>