获取当前系统时间，并将其以指定的格式存储在字符串中

        char time_buffer[20];
        auto now = std::chrono::system_clock::now();
        auto now_time = std::chrono::system_clock::to_time_t(now);
        std::strftime(time_buffer, sizeof(time_buffer), "%Y-%m-%d %H:%M:%S", std::localtime(&now_time));
        std::string current_time(time_buffer);