}
      Iterator<Integer> queueIterator = queue.iterator();
      int remaining = queue.size();
      while (queueIterator.hasNext()) {
        Integer element = queueIterator.next();
        remaining--;
        assertThat(elements).contains(element);
        if (random.nextBoolean()) {
          elements.remove(element);
          queueIterator.remove();
        }
      }

  }

  /**
   * Iterates the elements of the queue in no particular order.
   *
   * <p>If the underlying queue is modified during iteration an exception will be thrown.
   */
  private final class QueueIterator implements Iterator<E> {
    private int cursor = -1;
    private int nextCursor = -1;
    private int expectedModCount = modCount;