boost::asio::ip::tcp::socket& socket() const正在返回类型为boost::asio::ip::tcp::socket的_socket,并给出此错误
error:invalid initialization of non-const reference of type ‘boost::asi
[with C = boost::asio::basic_stream_socket<boost::asio::ip::tcp>; R = boost::system::error_code; Ps ='boost::system::error_code (boost::asio::basic_socket<boost::asi