chrono计算时间

# 计算时间

        auto start_time = std::chrono::steady_clock::now();
        CameraHandler();
        auto current_time = std::chrono::steady_clock::now();
        auto time = std::chrono::duration_cast<std::chrono::milliseconds>(current_time - start_time).count();
        
        std::cout << "Duration: " << time << " ms" << std::endl;
        printf("*************** time elapsed = %lld ms\n", time);