/** see {@link WorkerRunningState} */
  @LazyInit
  @GuardedBy("queue")
  private WorkerRunningState workerRunningState = IDLE;

  /**
   * This counter prevents an ABA issue where a thread may successfully schedule the worker, the
   * worker runs and exhausts the queue, another thread enqueues a task and fails to schedule the

                    return new SampleElements<>(
                        mapEntry("a", 1),
                        mapEntry("aa", 2),
                        mapEntry("aba", 3),
                        mapEntry("bbbb", 4),
                        mapEntry("ccccc", 5));
                  }

                  @Override

                    return new SampleElements<>(
                        mapEntry("a", 1),
                        mapEntry("aa", 2),
                        mapEntry("aba", 3),
                        mapEntry("bbbb", 4),
                        mapEntry("ccccc", 5));
                  }

                  @Override