anchor.diff:             cmd  => fun(#{domain := Domain} = State) ->
                              LAddr = which_local_addr(Domain),
                              LSA   = #{family => Domain, addr => LAddr},
  -                           {ok, State#{lsa => LSA}}
  +                           {ok, State#{local_sa => LSA}}
                      end},
            #{desc => "open socket",
              cmd  => fun(#{domain := Domain} = State) ->
  
positive.code:          %% to close the socket, which should cause the all the secondary 
           %% server to return with error-closed.
  
           #{desc => "order 'secondary server 1' to continue",
             cmd  => fun(#{sec_server1 := Pid} = _State) ->
                             Pid ! {continue, self()},
                             ok
                     end},
           #{desc => "sleep",
  
negative.code:                                    ERROR
                             end
                     end},
           #{desc => "announce ready (recv closed)",
             cmd  => fun(#{tester := Tester}) ->
                             ev_ready(Tester, recv_closed),
                             ok
                     end},
  
           %% Termination
           #{desc => "await terminate (from tester)",
             cmd  => fun(#{tester := Tester} = State) ->
                             case ev_await_terminate(Tester, tester) of
                                 ok ->
                                     {ok, maps:remove(tester, State)};
                                 {error, _} = ERROR ->
                                     ERROR
                             end
                     end},
  
  