`UnmodifiableMultimap.forEach` uses the `Multimap.forEach` default implementation which involves listing entries, and creating a new lambda instead of simply passing the BiConsumer through to the protected instance. This is safe to pass directly though because `forEach(BiConsumer)` is a read-only operation.
return AllEqualOrdering.INSTANCE;
  }
  /**
   * Returns an ordering that compares objects by the natural ordering of their string
   * representations as returned by {@code toString()}. It does not support null values.
   *
   * <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
   * {@code a == b} (identity equality). There is no meaning whatsoever to the order imposed, but it
   * is constant for the life of the VM.
   *
   * <p>Because the ordering is identity-based, it is not "consistent with {@link
   * Object#equals(Object)}" as defined by {@link Comparator}. Use caution when building a {@link
   * SortedSet} or {@link SortedMap} from it, as the resulting collection will not behave exactly
   * according to spec.
   *
   * <p>This ordering is not serializable, as its implementation relies on {@link
   * System#identityHashCode(Object)}, so its behavior cannot be preserved across serialization.
   *
   * @since 2.0
   */