title: How to check valid wsEngine on Engine.io (sockect.io)
body: <p>I've set my Socket.io <code>wsEngine</code> option as <code>uWs</code> like <a href="https://github.com/socketio/engine.io#methods-1" rel="nofollow">over here</a>.</p>
  
  <p>How can I check the valid <code>wsEngine</code> on <code>Socket.io</code>?</p>
  
  <p>Because I want to be sure about that which socket engine is being run by <code>Socket.io</code> library?</p>