code: func (s *SyncStatusSubscription) Unsubscribe() {
  	s.unsubOnce.Do(func() {
  		req := uninstallSyncSubscriptionRequest{s.c, make(chan interface{})}
  		s.api.uninstallSyncSubscription <- &req
  
  		for {
  			select {
  			case <-s.c:
  				// drop new status events until uninstall confirmation
  				continue
  			case <-req.uninstalled:
  				return
  			}
  		}
  	})
  }
docs: // Unsubscribe uninstalls the subscription from the DownloadAPI event loop.
  // The status channel that was passed to subscribeSyncStatus isn't used anymore
  // after this method returns.