编译不通过

g++ 版本 gcc version 4.8.5 20150623

speech_realtime_api/cpp-realtime-asr/mini/session.cpp:46:36: error: invalid initialization of non-const reference of type ‘std::istream& {aka std::basic_istream<char>&}’ from an rvalue of type ‘<brace-enclosed initializer list>’
           ws_{net::make_strand(ioc)} {
                                    ^