anchor.diff:  
       i("start server evaluator"),
       ServerInitState = #{domain => maps:get(domain, InitState),
  +                        proto  => maps:get(proto,  InitState),
                           recv   => maps:get(recv,   InitState)},
       Server = ?SEV_START("server", ServerSeq, ServerInitState),
   
       i("start client evaluator"),
       ClientInitState = #{host   => local_host(),
                           domain => maps:get(domain, InitState),
  +                        proto  => maps:get(proto,  InitState),
                           send   => maps:get(send, InitState)},
       Client = ?SEV_START("client", ClientSeq, ClientInitState),
   
  
positive.code:                            ok
                     end},
           #{desc => "order remote client to start",
             cmd  => fun(#{rclient := Client, server_sa := ServerSA}) ->
                             ?SEV_ANNOUNCE_START(Client, ServerSA),
                             ok
                     end},
           #{desc => "await remote client ready",
  
negative.code:     [
       sc_rs_recv_send_shutdown_receive_tcp4,
       sc_rs_recv_send_shutdown_receive_tcp6,
       sc_rs_recv_send_shutdown_receive_tcpL,
  
       sc_rs_recvmsg_send_shutdown_receive_tcp4,
       sc_rs_recvmsg_send_shutdown_receive_tcp6
  