public ImmutableSortedSet<E> elementSet() {
    return elementSet;
  }

  @Override
  public ImmutableSortedMultiset<E> headMultiset(E upperBound, BoundType boundType) {
    return getSubMultiset(0, elementSet.headIndex(upperBound, checkNotNull(boundType) == CLOSED));
  }

  @Override
  public ImmutableSortedMultiset<E> tailMultiset(E lowerBound, BoundType boundType) {
    return getSubMultiset(

        E head = oldTable.get(oldIndex);

        if (head != null) {
          E next = head.getNext();
          int headIndex = head.getHash() & newMask;

          // Single node on list
          if (next == null) {
            newTable.set(headIndex, head);
          } else {
            // Reuse the consecutive sequence of nodes with the same target