RegularImmutableSortedSet<E> elementSet, long[] cumulativeCounts, int offset, int length) {
    this.elementSet = elementSet;
    this.cumulativeCounts = cumulativeCounts;
    this.offset = offset;
    this.length = length;
  }

  private int getCount(int index) {
    return (int) (cumulativeCounts[offset + index + 1] - cumulativeCounts[offset + index]);
  }

  @Override
  Entry<E> getEntry(int index) {

      long[] cumulativeCounts = new long[length + 1];
      for (int i = 0; i < length; i++) {
        cumulativeCounts[i + 1] = cumulativeCounts[i] + counts[i];
      }
      forceCopyElements = true;
      return new RegularImmutableSortedMultiset<E>(elementSet, cumulativeCounts, 0, length);
    }
  }

  @J2ktIncompatible // serialization