docs: public void isEqualToDefaultInstance() {
      if (actual() == null) {
        failWithoutActual(
            simpleFact(
                lenientFormat(
                    "Not true that %s is a default proto instance. It is null.", actualAsString())));
      } else if (!actual().equals(actual().getDefaultInstanceForType())) {
        failWithoutActual(
            simpleFact(
                lenientFormat(
                    "Not true that %s is a default proto instance. It has set values.",
                    actualAsString())));
      }
    }