title: WebSocket request-response subprotocol
body: <p>WebSocket provides a bi-directional communication like a human being talks.
  The client can send data to the server and the server can send data to the client anytime.
  But what about the request-response behavior?
  The client could ask something to the server and wait for a response.
  It seems that Websocket doesn't provide anything to link client data (request) to server data (response).</p>
  
  <p>It's probably the work of the subprotocol and I have some ideas on how to do it (send an ID with the request and wait for a reponse with the same ID within a timeout period). </p>
  
  <p>In order to not reinvent the wheel and to save some time, I looked over the internet for an existing solution but I haven't found anything related (maybe bad keywords).</p>
  
  <p>So, is there anyone aware about this kind of work or am I missing something?</p>