start

inline fun <Req, Res> ServerStream<Req, Res>.start(el: String): ServerStreamStartActionBuilder<Req, Res>
inline fun <Req : Message, ReqBuilder : Message.Builder, Res> ServerStream<Req, Res>.start(crossinline newBuilder: () -> ReqBuilder, crossinline f: ReqBuilder.(Session) -> Req): ServerStreamStartActionBuilder<Req, Res>