class="el" href="classipc_1_1transport_1_1struc_1_1Msg__out.html" title="A structured out-message suitable to be sent via struc::Channel::send() (et al).">Msg_out</a> &amp;msg, const <a class="el" href="classipc_1_1transport_1_1struc_1_1Msg__in.html" title="A structured in-message instance suitable as received and emittable (to user) by struc::Channel.">Msg_in</a> *originating_msg_or_null, <a class="el" href="namespaceipc_1_1util.html#ac66141280c3b7295a86b65209f31cc58" title="Short-hand for Flow&#39;s Fine_