*
   * @return a new, empty {@code LinkedHashSet}
   */
  public static <E extends @Nullable Object> LinkedHashSet<E> newLinkedHashSet() {
    return new LinkedHashSet<>();
  }

  /**
   * Creates a <i>mutable</i> {@code LinkedHashSet} instance containing the given elements in order.
   *
   * <p><b>Note:</b> if mutability is not required and the elements are non-null, use {@link