Collections.addAll(all, e1, e2, e3, e4, e5, e6);
    Collections.addAll(all, others);
    return copyOf(all.iterator());
  }

  /** ImmutableSet.of API that is friendly to use from JavaScript. */
  @JsMethod(name = "of")
  static <E> ImmutableSet<E> jsOf(E... elements) {
    return copyOf(elements);
  }

  @JsMethod
  public static <E> ImmutableSet<E> copyOf(E[] elements) {