*
   * @since 19.0
   */
  public final boolean isSubtypeOf(Type supertype) {
    checkNotNull(supertype);
    if (supertype instanceof WildcardType) {
      // if 'supertype' is <? super Foo>, 'this' can be:
      // Foo, SubFoo, <? extends Foo>.
      // if 'supertype' is <? extends Foo>, nothing is a subtype.
      return any(((WildcardType) supertype).getLowerBounds()).isSupertypeOf(runtimeType);
    }

    TypeToken<TwoTypeArgs<?, ?>> supertype = new TypeToken<TwoTypeArgs<?, ?>>() {};
    TypeToken<StringForFirstTypeArg<String>> subtype =
        new TypeToken<StringForFirstTypeArg<String>>() {};
    assertTrue(subtype.isSubtypeOf(supertype));
    assertEquals(
        new TypeToken<StringForFirstTypeArg<?>>() {}, supertype.getSubtype(subtype.getRawType()));
  }

    TypeToken<TwoTypeArgs<?, ?>> supertype = new TypeToken<TwoTypeArgs<?, ?>>() {};
    TypeToken<StringForFirstTypeArg<String>> subtype =
        new TypeToken<StringForFirstTypeArg<String>>() {};
    assertTrue(subtype.isSubtypeOf(supertype));
    assertEquals(
        new TypeToken<StringForFirstTypeArg<?>>() {}, supertype.getSubtype(subtype.getRawType()));
  }