docs: public static <R> CloseableSpliterator<R> spliterator(BaseStream<R, Stream<R>> stream) {
        Spliterator<R> spliterator = stream.spliterator();
        if (spliterator instanceof CloseableSpliterator) {
           return (CloseableSpliterator<R>) spliterator;
        }
        return new StreamToCloseableSpliterator<>(stream, spliterator);
     }