title: Send intermittent status of request before sending actual response
body: <p>I have a server, which takes few minutes to process a specific request and then responds to it. </p>
  
  <p>The client has to keep waiting for the response without knowing when it will complete. </p>
  
  <p>Is there a way to let the client know about the processing status? (say 50% completed, 80% completed), without the client having to poll for the status. </p>