title: How to send a message to a particular client with socket.io
body: <p>I'm starting with socket.io + node.js, I know how to send a message locally and to broadcast <code>socket.broadcast.emit()</code> function:- all the connected clients receive the same message.</p>
  
  <p>Now, I would like to know how to send a private message to a particular client, I mean one socket for a private chat between 2 person (Client-To-Client stream). Thanks.</p>