如何让Boost Beast回复来自字符串而不是文件

#include <boost/asio.hpp>
#include <boost/beast.hpp>
#include <iostream>
#include <string>

namespace asio = boost::asio;
namespace beast = boost::beast;
using tcp = asio::ip::tcp;

int main() {
    asio::io_context io_context;

    // 创建TCP连接
    tcp::acceptor acceptor(io_context, tcp::endpoint(tcp::v4(), 8080));
    tcp::socket socket(io_context);
    acceptor.accept(socket);

    // 读取HTTP请求
    beast::flat_buffer buffer;
    beast::http::request<beast::http::string_body> request;
    beast::http::read(socket, buffer, request);

    // 构建HTTP响应
    beast::http::response<beast::http::string_body> response;
    response.version(request.version());
    response.result(beast::http::status::ok);
    response.set(beast::http::field::content_type, "text/plain");
    response.body() = "Hello, Boost Beast!";

    // 发送HTTP响应
    beast::http::write(socket, response);

    return 0;
}