}

    @Override
    public Iterator<Entry<K, V>> iterator() {
      return unmodifiableEntryIterator(entries.iterator());
    }

    // See java.util.Collections.UnmodifiableEntrySet for details on attacks.

    @Override
    public @Nullable Object[] toArray() {
      /*
       * standardToArray returns `@Nullable Object[]` rather than `Object[]` but because it can

      checkNotNull(element);
      contents.put(element, occurrences + contents.get(element));
      return this;
    }

    /**
     * Adds or removes the necessary occurrences of an element such that the element attains the
     * desired count.
     *
     * @param element the element to add or remove occurrences of
     * @param count the desired count of the element in this multiset
     * @return this {@code Builder} object

      elements[length] = element;
      counts[length] = occurrences;
      length++;
      return this;
    }

    /**
     * Adds or removes the necessary occurrences of an element such that the element attains the
     * desired count.
     *
     * @param element the element to add or remove occurrences of
     * @param count the desired count of the element in this multiset
     * @return this {@code Builder} object