anchor.diff:           %% *** Init part ***
            #{desc => "await start",
              cmd  => fun(State) ->
  -                           receive
  -                               {start, Tester} ->
  -                                   {ok, State#{tester => Tester}}
  -                           end
  +                           Tester = ev_await_start(),
  +                           ei("Tester: ~p", [Tester]),
  +                           {ok, State#{tester => Tester}}
                      end},
            #{desc => "monitor tester",
              cmd  => fun(#{tester := Tester} = _State) ->
  
positive.code:          %% *** Init part ***
           #{desc => "await start",
             cmd  => fun(State) ->
                             receive
                                 {start, Tester, Sock} ->
                                     {ok, State#{tester => Tester, sock => Sock}}
                             end
                     end},
           #{desc => "monitor tester",
             cmd  => fun(#{tester := Tester} = _State) ->
  
negative.code:            cmd  => fun(#{domain := Domain} = State) ->
                             LAddr = which_local_addr(Domain),
                             LSA   = #{family => Domain, addr => LAddr},
                             {ok, State#{local_sa => LSA}}
                     end},
           #{desc => "open socket",
             cmd  => fun(#{domain := Domain} = State) ->
  