anchor.diff:                             ok = Send(Sock, ?BASIC_REQ, Dst)
                      end},
            #{desc => "recv req (from src)",
  -           cmd  => fun(#{sock_dst := Sock, sa_src := Src, recv := Recv} = State) ->
  +           cmd  => fun(#{sock_dst := Sock, sa_src := Src, recv := Recv}) ->
                              {ok, {Src, ?BASIC_REQ}} = Recv(Sock),
                              ok
                      end},
  
positive.code:     Recv = fun(Sock) ->
                     socket:recv(Sock)
             end,
      ok = api_b_send_and_recv_tcp(inet, Send, Recv),
      tc_end().
  
  
  
negative.code: await_evaluator_finish(Evs, Fails) ->
      receive
          {'DOWN', _MRef, process, Pid, normal} ->
              case lists:delete(Pid, Evs) of
                  Evs ->
                      p("unknown process ~p died (normal)", [Pid]),
                      await_evaluator_finish(Evs, Fails);
  