Method wait

test/test_helpers.hpp:101–112

    explicit ThreadBarrier(size_t count) : threshold(count), count(count), generation(0) {}
    
    void wait() {
        std::unique_lock<std::mutex> lock(mutex);
        auto gen = generation;
        
        if (--count == 0) {
            generation++;
            count = threshold;
            cond.notify_all();
        } else {
            cond.wait(lock, [this, gen] { return gen != generation; });
        }
    }
    
private:
    std::mutex mutex;