Multipart stream

        if (state == null) return Collections.emptyList();
        long k = rand.nextLong();
        BitSet bitset = bitSetMap.computeIfAbsent(state, (s) -> IntStream.range(0, selectors.size()).filter((i) -> selectors.get(i).getLeft().test(s)).collect(BitSet::new, BitSet::set, BitSet::or));
        return bitset.stream().mapToObj(selectors::get).map(Pair::getRight).map(model -> model.getQuads(state, side, new Random(k), data)).flatMap(List::stream).collect(Collectors.toList());