* elements.
   *
   * @param distinctElements the expected number of distinct elements
   * @throws IllegalArgumentException if {@code distinctElements} is negative
   */
  public static <E extends @Nullable Object> HashMultiset<E> create(int distinctElements) {
    return new HashMultiset<>(distinctElements);
  }

  /**

    size += count - oldCount;
    if (oldCount == 0 && count > 0) {
      distinctElements++;
    } else if (oldCount > 0 && count == 0) {
      distinctElements--;
    }
    return oldCount;
  }

  @Override
  public void clear() {
    Arrays.fill(counts, 0);
    size = 0;
    distinctElements = 0;
  }

  abstract class Itr<T> implements Iterator<T> {
    int index = 0;

   */
  static <E extends @Nullable Object> void populateMultiset(
      Multiset<E> multiset, ObjectInputStream stream) throws IOException, ClassNotFoundException {
    int distinctElements = stream.readInt();
    populateMultiset(multiset, stream, distinctElements);
  }

  /**
   * Populates a multiset by reading an input stream, as part of deserialization. See {@link

   */
  static <E extends @Nullable Object> void populateMultiset(
      Multiset<E> multiset, ObjectInputStream stream) throws IOException, ClassNotFoundException {
    int distinctElements = stream.readInt();
    populateMultiset(multiset, stream, distinctElements);
  }

  /**
   * Populates a multiset by reading an input stream, as part of deserialization. See {@link

            }
          };
        }
      };
    }

    @Override
    public Iterator<E> iterator() {
      return Multisets.iteratorImpl(this);
    }

    @Override
    int distinctElements() {
      return backingMap.size();
    }
  }