docs: @Override
      public void registerNext(LaJobKey triggeredJobKey) { // uses triggered lock instead of synchronize
          verifyCanScheduleState();
          assertArgumentNotNull("triggeredJobKey", triggeredJobKey);
          // lazy check for initialization logic
          //if (!cron4jNow.findJobByKey(triggeredJobKey).isPresent()) {
          //    throw new IllegalArgumentException("Not found the job by the job key: " + triggeredJobKey);
          //}
          if (triggeredJobKey.equals(jobKey)) { // myself
              throw new IllegalArgumentException("Cannot register myself job as next trigger: " + toIdentityDisp());
          }
          synchronized (triggeredJobKeyLock) {
              if (triggeredJobKeyList == null) {
                  triggeredJobKeyList = new CopyOnWriteArraySet<LaJobKey>(); // just in case
              }
              triggeredJobKeyList.add(triggeredJobKey);
          }
      }