ObjectCountHashMap() {
    init(DEFAULT_SIZE, DEFAULT_LOAD_FACTOR);
  }

  ObjectCountHashMap(ObjectCountHashMap<? extends K> map) {
    init(map.size(), DEFAULT_LOAD_FACTOR);
    for (int i = map.firstIndex(); i != -1; i = map.nextIndex(i)) {
      put(map.getKey(i), map.getValue(i));
    }
  }

  /**
   * Constructs a new instance of {@code ObjectCountHashMap} with the specified capacity.
   *

   * enough it's not especially worth it.
   */
  abstract class Itr<T extends @Nullable Object> implements Iterator<T> {
    int entryIndex = backingMap.firstIndex();
    int toRemove = -1;
    int expectedModCount = backingMap.modCount;

    @ParametricNullness
    abstract T result(int entryIndex);

    private void checkForConcurrentModification() {