}

  @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) {

   *
   * @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 = Maps.safeGet(countMap, element);
      if (existingCounter == null) {

     *
     * @return the count of {@code element} in the multiset before this call
     * @throws IllegalArgumentException if {@code count} is negative
     */
    @Override
    public int setCount(E element, int count) {
      checkNonnegative(count, "count");
      return (count == 0) ? removeAllOccurrences(element) : unbox(countMap.put(element, count));
    }

    /**

      }
    }

    @Override
    public int setCount(@ParametricNullness E element, int count) {
      synchronized (mutex) {
        return delegate().setCount(element, count);
      }
    }

    @Override
    public boolean setCount(@ParametricNullness E element, int oldCount, int newCount) {
      synchronized (mutex) {
        return delegate().setCount(element, oldCount, newCount);
      }
    }

    }

    frequency.add(-numberRemoved);
    size -= numberRemoved;
    return oldCount;
  }

  // Roughly a 33% performance improvement over AbstractMultiset.setCount().
  @CanIgnoreReturnValue
  @Override
  public int setCount(@ParametricNullness E element, int count) {
    checkNonnegative(count, "count");

    Count existingCounter;
    int oldCount;
    if (count == 0) {

   *     zero instead.
   */
  @CanIgnoreReturnValue
  int setCount(@ParametricNullness E element, int count);

  /**
   * Conditionally sets the count of an element to a new value, as described in {@link
   * #setCount(Object, int)}, provided that the element has the expected current count. If the
   * current count is not {@code oldCount}, no change is made.
   *

     *
     * @return the count of {@code element} in the multiset before this call
     * @throws IllegalArgumentException if {@code count} is negative
     */
    @Override
    public int setCount(E element, int count) {
      checkNonnegative(count, "count");
      return (count == 0) ? removeAllOccurrences(element) : unbox(countMap.put(element, count));
    }

    /**

    assertTrue(
        "setCount() with the correct expected present count should return true",
        setCount(element, count));
  }

  @Override
  void setCountNoCheckReturnValue(E element, int count) {
    setCount(element, count);
  }

  @CanIgnoreReturnValue
  private boolean setCount(E element, int count) {
    return getMultiset().setCount(element, getMultiset().count(element), count);
  }

   *
   * @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 = Maps.safeGet(countMap, element);
      if (existingCounter == null) {

    } else {
      counts[index] = oldCount - occurrences;
      size -= occurrences;
    }
    return oldCount;
  }

  // Modification Operations
  @CanIgnoreReturnValue
  @Override
  public int setCount(E element, int count) {
    checkIsE(element);
    checkNonnegative(count, "count");
    int index = element.ordinal();
    int oldCount = counts[index];
    counts[index] = count;
    size += count - oldCount;