code: protected void append0 (T item, boolean notify)
      {
          if (_count == _size) {
              makeMoreRoom();
          }
          _items[_end] = item;
          _end = (_end + 1) % _size;
          _count++;
  
          if (notify) {
              notify();
          }
      }
docs: Internal append method. If subclassing queue, be sure to call
  this method from inside a synchronized block.