public override void HandleEventsForBackgroundUrl(UIApplication application, string sessionIdentifier, Action completionHandler)
 {
     if (HandleEventsForBackgroundUrlEvent != null)
     {
         BackgroundUrlEventArgs args = new BackgroundUrlEventArgs (application, sessionIdentifier, completionHandler);
         HandleEventsForBackgroundUrlEvent.Invoke (this, args);
     }
 }
 protected void HandleEventsForBackgroundUrl(object sender, BackgroundUrlEventArgs args)
 {
     // after all is done:
     args.completionHandler.Invoke ();
 }