*/
  @SuppressWarnings("NonApiType") // acts as a direct substitute for a constructor call
  public static <E extends @Nullable Object> HashSet<E> newHashSet(E... elements) {
    HashSet<E> set = newHashSetWithExpectedSize(elements.length);
    Collections.addAll(set, elements);
    return set;
  }

  /**
   * Creates a <i>mutable</i> {@code HashSet} instance containing the given elements. A very thin