multiset.add(key, delta);
              deltas[keyIndex] += delta;
              break;
            }
          case SET_COUNT:
            {
              int newValue = random.nextInt(3);
              int oldValue = multiset.setCount(key, newValue);
              deltas[keyIndex] += newValue - oldValue;
              break;
            }
          case SET_COUNT_IF:
            {

    }
    int[] result = new int[1]; // used as a mutable int reference to hold result
    AvlNode<E> newRoot = root.setCount(comparator(), element, count, result);
    rootReference.checkAndSet(root, newRoot);
    return result[0];
  }

  @CanIgnoreReturnValue
  @Override
  public boolean setCount(@ParametricNullness E element, int oldCount, int newCount) {
    checkNonnegative(newCount, "newCount");

    }
    int[] result = new int[1]; // used as a mutable int reference to hold result
    AvlNode<E> newRoot = root.setCount(comparator(), element, count, result);
    rootReference.checkAndSet(root, newRoot);
    return result[0];
  }

  @CanIgnoreReturnValue
  @Override
  public boolean setCount(@ParametricNullness E element, int oldCount, int newCount) {
    checkNonnegative(newCount, "newCount");

  }

  @CanIgnoreReturnValue
  @Override
  public final int setCount(@ParametricNullness E element, int count) {
    checkNonnegative(count, "count");
    int oldCount = (count == 0) ? backingMap.remove(element) : backingMap.put(element, count);
    size += (count - oldCount);
    return oldCount;
  }

  @Override
  public final boolean setCount(@ParametricNullness E element, int oldCount, int newCount) {

    when(backingMap.remove(KEY, current)).thenReturn(true);

    assertEquals(countToRemove, multiset.setCount(KEY, 0));
    assertEquals(0, current.get());
  }

  public void testSetCount_0_nonePresent() {
    when(backingMap.get(KEY)).thenReturn(null);

    assertEquals(0, multiset.setCount(KEY, 0));
  }

  public void testSerialCycle() {

   *
   * @return the count of {@code element} in the multiset before this call
   * @throws IllegalArgumentException if {@code count} is negative
   */
  @CanIgnoreReturnValue
  @Override
  public int setCount(E element, int count) {
    checkNotNull(element);
    checkNonnegative(count, "count");
    while (true) {
      AtomicInteger existingCounter = safeGet(countMap, element);
      if (existingCounter == null) {