* k <= i < n}.
   *
   * <p>After this method returns, {@code elements} will contain no duplicates, but {@code elements}
   * may be the real array backing the returned set, so do not modify it further.
   *
   * <p>{@code elements} may contain only values of type {@code E}.
   *
   * @throws NullPointerException if any of the first {@code n} elements of {@code elements} is null

    return new SingletonImmutableSet<>(element);
  }

  /*
   * TODO: b/315526394 - Skip the Builder entirely for the of(...) methods, since we don't need to
   * worry that we might trigger the fallback to the JDK-backed implementation? (The varargs one
   * _could_, so we could keep it as it is. Or we could convince ourselves that hash flooding is
   * unlikely in practice there, too.)
   */

  /**