anchor.diff:  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   
   api_b_send_and_recv_udp(InitState) ->
  -    %% SockSrc = sock_open(Domain, dgram, udp),
  -    %% LAddr   = which_local_addr(Domain),
  -    %% LSA     = #{family => Domain, addr => LAddr}, 
  -    %% sock_bind(SockSrc, LSA),
  -    %% SockDst = sock_open(Domain, dgram, udp),
  -    %% sock_bind(SockDst, LSA),
  -    %% Dst     = sock_sockname(SockDst),
  -    %% ok      = Send(SockSrc, ?BASIC_REQ, Dst),
  -    %% {ok, {Src, ?BASIC_REQ}} = Recv(SockDst),
  -    %% ok      = Send(SockDst, ?BASIC_REP, Src),
  -    %% {ok, {Dst, ?BASIC_REP}} = Recv(SockSrc),
  -    %% socket:close(SockSrc),
  -    %% socket:close(SockDst),
       Seq = 
           [
            #{desc => "local address",
  
positive.code:                            ok = Send(Sock, ?BASIC_REQ, Dst)
                     end},
           #{desc => "recv req (from src)",
             cmd  => fun(#{sock_dst := Sock, sa_src := Src, recv := Recv} = State) ->
                             {ok, {Src, ?BASIC_REQ}} = Recv(Sock),
                             ok
                     end},
  
negative.code:                     await_evaluator_finish(NewEvs, Fails)
              end;
          {'DOWN', _MRef, process, Pid, Reason} ->
              case lists:delete(Pid, Evs) of
                  Evs ->
                      p("unknown process ~p died: "
                          "~n   ~p", [Pid, Reason]),
  