* <p>The comparator is serializable.
   *
   * <p><b>Java 8+ users:</b> Use {@code Comparator.comparing(Object::toString)} instead.
   */
  @GwtCompatible(serializable = true)
  public static Ordering<Object> usingToString() {
    return UsingToStringOrdering.INSTANCE;
  }

  /**
   * Returns an arbitrary ordering over all objects, for which {@code compare(a, b) == 0} implies