void testWithCache2(const std::vector<double>& testSequence,
         int iteration)
 {
     using namespace std::chrono;
     auto start = std::chrono::system_clock::now();
     for (int i = 0; i < iteration; ++i) {
         auto d = m_cache.castToStr(testSequence[i]);
     }
     auto finish = std::chrono::system_clock::now();
     auto duration = finish - start;
     std::cout << "with cache, mean latency: "
         << duration_cast<nanoseconds>(duration).count() / iteration
         << " ns, cache miss ratio: "
         << m_cache.missRatio()<<"%"<<std::endl;
 }