docs: private boolean cleanupTimer() {
      TimerTask timerTask = CANCEL_TIMER_UPDATER.get(this);
      if (timerTask == null) {
        // If timeout is zero, then timer task did not exist, so we safely report "all clear"
        return timeout == 0;
      }
      if (!CANCEL_TIMER_UPDATER.compareAndSet(this, timerTask, null)) {
        // Failed to update reference -> timer has just fired, so we must wait for the query state to
        // become "cancelling".
        return false;
      }
      timerTask.cancel();
      connection.purgeTimerTasks();
      // All clear
      return true;
    }