return new TreeMultiset<>(
        rootReference,
        range.intersect(GeneralRange.upTo(comparator(), upperBound, boundType)),
        header);
  }

  @Override
  public SortedMultiset<E> tailMultiset(@ParametricNullness E lowerBound, BoundType boundType) {
    return new TreeMultiset<>(
        rootReference,
        range.intersect(GeneralRange.downTo(comparator(), lowerBound, boundType)),
        header);
  }

    assertEquals(Integer.MAX_VALUE, ms.headMultiset("a", CLOSED).size());

    assertEquals(3, ms.tailMultiset("c", CLOSED).size());
    assertEquals(Integer.MAX_VALUE, ms.tailMultiset("b", CLOSED).size());
    assertEquals(Integer.MAX_VALUE, ms.tailMultiset("a", CLOSED).size());
  }

  @J2ktIncompatible
  @GwtIncompatible // reflection