public void startListeningForUpdates(
     DownloadId downloadId, List<DownloadWatcher> downloadWatchers) {
   attachWatchers(downloadWatchers);
   progressController.register();
   broadcastStart(downloadId);
   watcherService.startWatching();
 }
 @Override
 public void onAllFinished() {
   progressController.unregister();
 }