code: public final void submit(Queue<E> queue, E item) throws ConcurrentConveyorException {
          for (long idleCount = 0; !queue.offer(item); idleCount++) {
              SUBMIT_IDLER.idle(idleCount);
              checkDrainerGone();
              unparkDrainer();
              checkInterrupted();
          }
          for (long idleCount = 0; backpressure; idleCount++) {
              SUBMIT_IDLER.idle(idleCount);
              checkInterrupted();
          }
      }
docs: Blocks until successfully inserting the given item to the given queue.
  No check is performed that the queue actually belongs to this conveyor.
  If the {@code #backpressure} flag is raised on this conveyor at the time
  the item has been submitted, further blocks until the flag is lowered.
  
  @throws ConcurrentConveyorException if the current thread is interrupted
  or the draining thread has already left