@Override
    public void increment() {
      getAndIncrement();
    }

    @Override
    public void add(long x) {
      getAndAdd(x);
    }

    @Override
    public long sum() {
      return get();
    }
  }

  private LongAddables() {}

   */
  @CanIgnoreReturnValue
  public long getAndIncrement(K key) {
    return getAndAdd(key, 1);
  }

  /**
   * Decrements by one the value currently associated with {@code key}, and returns the old value.
   */
  @CanIgnoreReturnValue
  public long getAndDecrement(K key) {
    return getAndAdd(key, -1);
  }

  /**

                      case 4:
                        map.getAndDecrement(key);
                        threadSum--;
                        break;
                      case 5:
                        map.getAndAdd(key, delta);
                        threadSum += delta;
                        break;
                      case 6:
                        long oldValue = map.put(key, delta);