SortedSet<String> subset = elementSet.subSet("b", "f");
    assertThat(subset).containsExactly("b", "c", "d", "e").inOrder();

    assertTrue(subset.remove("c"));
    assertThat(elementSet).containsExactly("a", "b", "d", "e", "f").inOrder();
    assertThat(subset).containsExactly("b", "d", "e").inOrder();
    assertEquals(10, ms.size());

    assertFalse(subset.remove("a"));

    assertThat(set.subSet(1, 4)).containsExactly(1, 2, 3).inOrder();
    assertThat(set.subSet(2, 4)).containsExactly(2, 3).inOrder();
    assertThat(set.subSet(3, 4)).containsExactly(3).inOrder();
    assertThat(set.subSet(3, 3)).isEmpty();
    assertThat(set.subSet(2, 3)).containsExactly(2).inOrder();
    assertThat(set.subSet(1, 3)).containsExactly(1, 2).inOrder();

    assertThat(set.subSet(1, 4)).containsExactly(1, 2, 3).inOrder();
    assertThat(set.subSet(2, 4)).containsExactly(2, 3).inOrder();
    assertThat(set.subSet(3, 4)).containsExactly(3).inOrder();
    assertThat(set.subSet(3, 3)).isEmpty();
    assertThat(set.subSet(2, 3)).containsExactly(2).inOrder();
    assertThat(set.subSet(1, 3)).containsExactly(1, 2).inOrder();

    SortedSet<String> subSet = set.subSet("a", "b");
    assertTrue(subSet instanceof SynchronizedSortedSet);
    assertSame(set, ((SynchronizedSortedSet<String>) subSet).mutex);
  }

  public void testSubSet_E_B_E_B() {
    NavigableSet<String> set = create();
    NavigableSet<String> subSet = set.subSet("a", false, "b", true);
    assertTrue(subSet instanceof SynchronizedNavigableSet);

    SortedSet<String> subSet = map.subSet("a", "b");
    assertTrue(subSet instanceof SynchronizedSortedSet);
    assertSame(MUTEX, ((SynchronizedSortedSet<String>) subSet).mutex);
  }

  public void testSubSet_E_B_E_B() {
    NavigableSet<String> map = create();
    NavigableSet<String> subSet = map.subSet("a", false, "b", true);
    assertTrue(subSet instanceof SynchronizedNavigableSet);

  }

  public void testSingle_subSet() {
    SortedSet<String> set = of("e");
    assertTrue(set.subSet("c", "g") instanceof ImmutableSortedSet);
    assertThat(set.subSet("c", "g")).contains("e");
    assertThat(set.subSet("e", "g")).contains("e");
    assertSame(this.<String>of(), set.subSet("f", "g"));
    assertSame(this.<String>of(), set.subSet("c", "e"));
    assertSame(this.<String>of(), set.subSet("c", "d"));

   * boolean, Object, boolean)} method. If you override {@link #subSet(Object, boolean, Object,
   * boolean)}, you may wish to override {@link #subSet(Object, Object)} to forward to this
   * implementation.
   */
  @Override
  protected SortedSet<E> standardSubSet(
      @ParametricNullness E fromElement, @ParametricNullness E toElement) {

	sort.Slice(clusters, func(i, j int) bool {
		iDirection, iSubset, iName, iPort := safelyParseSubsetKey(clusters[i].Name)
		jDirection, jSubset, jName, jPort := safelyParseSubsetKey(clusters[j].Name)
		if iName == jName {
			if iSubset == jSubset {
				if iPort == jPort {
					return iDirection < jDirection
				}
				return iPort < jPort
			}
			return iSubset < jSubset
		}
		return iName < jName
	})

    assertEquals(ImmutableSortedSet.of(4, 6, 8, 10), Sets.subSet(set, Range.atLeast(4)));
    assertEquals(ImmutableSortedSet.of(8, 10), Sets.subSet(set, Range.atLeast(7)));
    assertEquals(empty, Sets.subSet(set, Range.atLeast(20)));

    assertEquals(set, Sets.subSet(set, Range.greaterThan(0)));
    assertEquals(ImmutableSortedSet.of(6, 8, 10), Sets.subSet(set, Range.greaterThan(4)));

      } else if (from == Bound.EXCLUSIVE && to == Bound.EXCLUSIVE) {
        return set.subSet(firstExclusive, false, lastExclusive, false);
      } else if (from == Bound.EXCLUSIVE && to == Bound.INCLUSIVE) {
        return set.subSet(firstExclusive, false, lastInclusive, true);
      } else if (from == Bound.INCLUSIVE && to == Bound.INCLUSIVE) {
        return set.subSet(firstInclusive, true, lastInclusive, true);
      } else {