title: hapijs v18 send response before handler completion
body: <p>I want to send a response from my hapijs handler before the handler completes.
  I have tried <code>h.response().code(204).takeover()</code> however the response doesn't appear to be sent until it is explicitly returned from the handler and the documentation suggests the same.
  I want to immediately return a 204 and then continue running code in the handler. Is there a way to continue processing after a response is sent?
  The documentation for request.generateResponse() suggests that the reply interface can be used but I think this is just a documentation error as the reply interface links back to the response toolkit documentation.</p>