title: async http request handling
body: <p>I'm trying to handle an HTTP request in Go asynchronously this way:</p>
  
  <ol>
  <li>I pass a handler function to the HTTP server</li>
  <li>In the handler I store the HttpRequest / HttpResponse objects in a slice or a map</li>
  <li>When returning from the handler function - the response is NOT returned to the client, but the connection remains open</li>
  <li>When "some" async input received from another source, I take the relevant HttpRequest / HttpResponse objects from memory, write the response and close the connection.</li>
  </ol>
  
  <p>What I aim for is very similar to Jetty-Continuation in Java.</p>
  
  <p>How can I implement such a behaviour in GoLang?</p>