* instead.
   *
   * @throws NullPointerException if {@code comparator} is null
   */
  public static <E> Builder<E> orderedBy(Comparator<E> comparator) {
    return new Builder<>(comparator);
  }

  /**
   * Returns a builder that creates immutable sorted sets whose elements are ordered by the reverse
   * of their natural ordering.
   */
  public static <E extends Comparable<?>> Builder<E> reverseOrder() {

   * instead.
   *
   * @throws NullPointerException if {@code comparator} is null
   */
  public static <E> Builder<E> orderedBy(Comparator<E> comparator) {
    return new Builder<>(comparator);
  }

  /**
   * Returns a builder that creates immutable sorted sets whose elements are ordered by the reverse
   * of their natural ordering.
   */
  public static <E extends Comparable<?>> Builder<E> reverseOrder() {

      if (tmp == null) {
        return emptySet(comparator());
      }
      fromElement = tmp;
    }
    return tailSet(fromElement);
  }

  public static <E> Builder<E> orderedBy(Comparator<E> comparator) {
    return new Builder<E>(comparator);
  }

  public static <E extends Comparable<?>> Builder<E> reverseOrder() {
    return new Builder<E>(Ordering.natural().reverse());
  }