docs: static <R> BiPredicate<R, Throwable> failurePredicateFor(List<Class<? extends Throwable>> failures) {
      return (t, u) -> {
        if (u == null)
          return false;
        for (Class<? extends Throwable> failureType : failures)
          if (failureType.isAssignableFrom(u.getClass()))
            return true;
        return false;
      };
    }