有没有办法通过协程获得在Boost asio中传输的字节数

#include <iostream>
#include <boost/asio.hpp>
#include <boost/asio/spawn.hpp>

using boost::asio::ip::tcp;

int main()
{
    boost::asio::io_context io_context;

    tcp::acceptor acceptor(io_context, tcp::endpoint(tcp::v4(), 1234));
    tcp::socket socket(io_context);

    boost::asio::spawn(io_context, [&](boost::asio::yield_context yield)
    {
        boost::system::error_code ec;

        // 等待连接
        acceptor.async_accept(socket, yield[ec]);
        if (ec)
        {
            std::cerr << "Error accepting connection: " << ec.message() << std::endl;
            return;
        }

        // 读取数据
        std::array<char, 1024> buffer;
        size_t bytes_transferred = boost::asio::async_read(socket, boost::asio::buffer(buffer), yield[ec]);
        if (ec)
        {
            std::cerr << "Error reading data: " << ec.message() << std::endl;
            return;
        }

        std::cout << "Received " << bytes_transferred << " bytes" << std::endl;
    });

    io_context.run();

    return 0;
}