@Override
    public abstract int size();

    abstract Iterator<Entry<K, V>> entryIterator();

    Spliterator<Entry<K, V>> entrySpliterator() {
      return Spliterators.spliterator(
          entryIterator(), size(), Spliterator.SIZED | Spliterator.DISTINCT);
    }

    @Override
    public Set<Entry<K, V>> entrySet() {
      return new EntrySet<K, V>() {
        @Override