case ADD:
            {
              int delta = random.nextInt(10);
              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;

          int key2 = key1 ^ delta;

          // get hashes
          int hash1 = function.hashInt(key1).asInt();
          int hash2 = function.hashInt(key2).asInt();

          // this 2-bit candidate delta is not a characteristic
          // if deltas are different
          if ((hash1 ^ hash2) != delta) {
            diff = true;
            continue;
          }

            Long.MIN_VALUE,
            Long.MAX_VALUE)) {
      for (double delta : Doubles.asList(0.0, 1.0, 2.0)) {
        integralBuilder.addAll(Doubles.asList(d + delta, d - delta, -d - delta, -d + delta));
      }
      for (double delta : Doubles.asList(0.01, 0.1, 0.25, 0.499, 0.5, 0.501, 0.7, 0.8)) {
        double x = d + delta;
        if (x != Math.round(x)) {
          fractionalBuilder.add(x);
        }
      }

  public long decrementAndGet(K key) {
    return addAndGet(key, -1);
  }

  /**
   * Adds {@code delta} to the value currently associated with {@code key}, and returns the new
   * value.
   */
  @CanIgnoreReturnValue
  public long addAndGet(K key, long delta) {
    return accumulateAndGet(key, delta, Long::sum);
  }

  /**

    final List<E> delegate;
    final int delta;

    MisleadingSizeList(List<E> delegate, int delta) {
      this.delegate = delegate;
      this.delta = delta;
    }

    @Override
    protected List<E> delegate() {
      return delegate;
    }

    @Override
    public int size() {
      return delegate.size() + delta;
    }
  }

   * size() as a hint only.
   *
   * @param delta the difference between the true size of the collection and the values returned by
   *     the size method
   */
  public static <T extends @Nullable Object> Collection<T> misleadingSizeCollection(int delta) {
    // It would be nice to be able to return a real concurrent

  /** The Greek letter delta, used in unicode testing. */
  private static final String DELTA = "\u0394";

  /** A domain part which is valid under lenient validation, but invalid under strict validation. */
  @SuppressWarnings("InlineMeInliner") // String.repeat unavailable under Java 8
  static final String LOTS_OF_DELTAS = Strings.repeat(DELTA, 62);

  }

  public void testToArray_threadSafe() {
    for (int delta : new int[] {+1, 0, -1}) {
      for (int i = 0; i < VALUES.length; i++) {
        List<Byte> list = Bytes.asList(VALUES).subList(0, i);
        Collection<Byte> misleadingSize = Helpers.misleadingSizeCollection(delta);
        misleadingSize.addAll(list);
        byte[] arr = Bytes.toArray(misleadingSize);

      // http://graphics.stanford.edu/~seander/bithacks.html#IntegerMinOrMax

      long delta = a - b; // can't overflow, since a and b are nonnegative

      long minDeltaOrZero = delta & (delta >> (Long.SIZE - 1));
      // equivalent to Math.min(delta, 0)

      a = delta - minDeltaOrZero - minDeltaOrZero; // sets a to Math.abs(a - b)
      // a is now nonnegative and even

  }

  public void testToArray_threadSafe() {
    for (int delta : new int[] {+1, 0, -1}) {
      for (int i = 0; i < VALUES.length; i++) {
        List<Character> list = Chars.asList(VALUES).subList(0, i);
        Collection<Character> misleadingSize = Helpers.misleadingSizeCollection(delta);
        misleadingSize.addAll(list);
        char[] arr = Chars.toArray(misleadingSize);