code: public void triggerRegisteredAppUsageObserver(int observerId, long timeUsedInMillis) {
      AppUsageObserver observer = appUsageObserversById.remove(observerId);
      long timeLimitInMillis = observer.timeUnit.toMillis(observer.timeLimit);
      Intent intent =
          new Intent()
              .putExtra(UsageStatsManager.EXTRA_OBSERVER_ID, observerId)
              .putExtra(UsageStatsManager.EXTRA_TIME_LIMIT, timeLimitInMillis)
              .putExtra(UsageStatsManager.EXTRA_TIME_USED, timeUsedInMillis);
      try {
        observer.callbackIntent.send(RuntimeEnvironment.application, 0, intent);
      } catch (CanceledException e) {
        throw new RuntimeException(e);
      }
    }
docs: Triggers a currently registered {@link AppUsageObserver} with {@code observerId}.
  
  <p>The observer will be no longer registered afterwards.