anchor.diff:  sleep(Pid, Time) ->
       Pid ! {'$gen_component', time, Time}.
   
  +%% @edoc change the handler for handling messages
  +change_handler(State, Handler) when is_atom(Handler) ->
  +    {'$gen_component', [{on_handler, Handler}], State}.
  +
   %================================================================================
   % generic framework
   %================================================================================
  
positive.code:                             %io:format("slow message ~p (~p)~n", [Message, Span]),
                              %loop(Module, NewState, {Options, Span});
                          %true ->
                              loop(Module, NewState, {Options, Slowest})
                      %end
              end
      end.
  
negative.code: 
  -export([behaviour_info/1]).
  
  -export([start_link/2, start_link/3, start/4, start/2, start/3,wait_for_ok/0,
           change_handler/2]).
  
  -export([kill/1, sleep/2]).
  
  