title: GWT Servlet-based Notification (Server Event Bus)
body: <p>Can anyone think of a good way to allow the server to notify the client based upon server processing? For example, consider the following events:</p>
  
  <ol>
  <li>A user requests a deletion of data, however, due to it's long-running time, we kick it off to a queue.</li>
  <li>The client receives a "Yes we completed your transaction successfully".</li>
  <li>The server deletes the item and now wants to update any local structures any clients may be using (I'd also like to notify the user).</li>
  </ol>
  
  <p>I know this can be done by client-side polling. Is there a event bus type way to do this? Any suggestions are welcome, but please keep in mind I am using GWT with App Engine.</p>