void PlaybackController_OnProgress(object sender, PlaybackStateEventArgs e)
 {
     if (!UpdatePosition(e.Title, e.Position))
     {
         PlaybackController.OnProgress -= new EventHandler<PlaybackStateEventArgs>(PlaybackController_OnProgress);
     }
 }
 void ExternalItem_OnProgress(object sender, PlaybackStateEventArgs e)
 {
     //do nothing - we are used when something is already playing when we are created
 }