@Override
  public void run() {
    if (mShouldStop) {
      return;
    }

    long now = mClock.nowMillis();
    long counterValue = getCounterValue(now);
    if (mLastSeenCounterValue != counterValue) {
      mLastSeenCounterValue = counterValue;
      fireTotpCounterValueChanged();
    }
    fireTotpCountdown(getTimeTillNextCounterValue(now));

    scheduleNextInvocation();
  }
Stops this task. This task will never notify the listener after the task has been stopped.
java/com/google/android/apps/authenticator/otp/TotpCountdownTask.java