title: Observe the ping of socketio client at server side
body: <p>I know that the socketio client sends a ping at every 25 secs (heartbeat interval) and gets a response back from the server. I want to print this ping from client on the server side and also if possible capture the ping response sent back by the node server.</p>
  
  <p>I tried using </p>
  
  <pre><code>socket.on("ping", function(data) {
      console.log("received ping");
  });
  socket.on("pong", function(data) {
      console.log("received pong");
  });
  </code></pre>
  
  <p>both on client and the server side but i am not able to capture them</p>