        void handle_header()
        {
            // HTTP 1.1 Expect: 100-continue
            if (req_.http_ver_major == 1 && req_.http_ver_minor == 1 && get_header_value(req_.headers, "expect") == "100-continue")
            {
                buffers_.clear();
                static std::string expect_100_continue = "HTTP/1.1 100 Continue\r\n\r\n";
                buffers_.emplace_back(expect_100_continue.data(), expect_100_continue.size());
                do_write();
            }
        }
        void handle_header()
        {
             
            if (req_.http_ver_major == 1 && req_.http_ver_minor == 1 && get_header_value(req_.headers, "expect") == "100-continue")
            {
                buffers_.clear();
                static std::string expect_100_continue = "HTTP/1.1 100 Continue\r\n\r\n";
                buffers_.emplace_back(expect_100_continue.data(), expect_100_continue.size());
                do_write();
            }
        }