bool JvmtiDeferredEventQueue::has_events() {

  {- -------------------------------------------
  (1) (assert)
      ---------------------------------------- -}

      assert(Service_lock->owned_by_self(), "Must own Service_lock");

  {- -------------------------------------------
  (1) 中身が入っていれば true をリターン.
      ---------------------------------------- -}

      return _queue_head != NULL || _pending_list != NULL;
    }