*/
  @Override
  public ImmutableSortedMap<K, V> tailMap(K fromKey) {
    return tailMap(fromKey, true);
  }

  /**
   * This method returns a {@code ImmutableSortedMap}, consisting of the entries whose keys are
   * greater than (or equal to, if {@code inclusive}) {@code fromKey}.
   *
   * <p>The {@link SortedMap#tailMap} documentation states that a submap of a submap throws an

    }

    @Override
    public NavigableMap<K, V> tailMap(K fromKey, boolean inclusive) {
      synchronized (mutex) {
        return navigableMap(delegate().tailMap(fromKey, inclusive), mutex);
      }
    }

    @Override
    public SortedMap<K, V> tailMap(K fromKey) {
      return tailMap(fromKey, true);
    }

    }

    @Override
    public NavigableMap<K, V> tailMap(K fromKey, boolean inclusive) {
      synchronized (mutex) {
        return navigableMap(delegate().tailMap(fromKey, inclusive), mutex);
      }
    }

    @Override
    public SortedMap<K, V> tailMap(K fromKey) {
      return tailMap(fromKey, true);
    }

   */
  @Override
  public ImmutableSortedMap<K, V> tailMap(K fromKey) {
    return tailMap(fromKey, true);
  }

  /**
   * This method returns a {@code ImmutableSortedMap}, consisting of the entries whose keys are
   * greater than (or equal to, if {@code inclusive}) {@code fromKey}.
   *
   * <p>The {@link SortedMap#tailMap} documentation states that a submap of a submap throws an

        .inOrder();
    assertEquals(map.headMap("three", true), map.descendingMap().tailMap("three", true));
    assertThat(map.tailMap("three", false).entrySet()).contains(mapEntry("two", 3));
    assertThat(map.tailMap("three", true).lowerEntry("three")).isNull();
    assertThat(map.headMap("two", false).values()).containsExactly(3, 5).inOrder();