if (forgetMeNot == null || skipMe == null) {
            forgetMeNot = new ArrayDeque<>();
            skipMe = new ArrayList<>(3);
          }
          if (!foundAndRemovedExactReference(skipMe, moved.toTrickle)) {
            forgetMeNot.add(moved.toTrickle);
          }
          if (!foundAndRemovedExactReference(forgetMeNot, moved.replaced)) {
            skipMe.add(moved.replaced);
          }
        }

  }

  /**
   * This tests a special case where removeAt has to trickle an element first down one level from a
   * min to a max level, then up one level above the index of the removed element. It also tests
   * that skipMe in the iterator plays nicely with forgetMeNot.
   */
  public void testIteratorInvalidatingIteratorRemove2() {
    MinMaxPriorityQueue<Integer> mmHeap = MinMaxPriorityQueue.create();
    mmHeap.addAll(