copy_if_impl

template <typename Container, typename Predicate>
vector<typename Container::value_type> CopyIfUnordered(const Container& vec, Predicate p) {
    std::vector<typename Container::value_type> out;
    std::mutex mut;
    std::for_each(std::execution::par, begin(vec), end(vec),
        [&out, &mut, p](auto&& elem) {
            if (p(elem)) {
                std::unique_lock lock(mut);
                out.push_back(elem);
            }
        });

    return out;
 }