anchor.diff:  
   -export([start/0, stop/0,
            reset_events/0,
  -         events/0,
  +         events/0, events/1,
            log/1]).
   -export([timestamp/0, format_timestamp/1]).
   -export([init/1]).
  
positive.code:     call(reset_events, ?TIMEOUT).
  
  events() ->
      call(events, ?TIMEOUT).
  
  log(Event) ->
      cast({node(), Event}).
  
negative.code:                     NamePid when is_pid(NamePid) ->
                          receive
                              {?MODULE, Ref, Rep} ->
                                  exit(Rep)
                          after Timeout2 ->
                                  {error, timeout}
                          end
  