anchor.diff:      receive
           ?SCALARIS_RECV({get_trace_reply, Log}, Log)
       end.
  +
  +-spec cleanup() -> ok.
  +cleanup() -> cleanup(default).
   
   -spec cleanup(trace_id()) -> ok.
   cleanup(TraceId) ->
  
positive.code: 
  %% client functions
  -export([start/0, start/1, start/2, stop/0]).
  -export([get_trace/0, get_trace/1, cleanup/1]).
  
  %% trace analysis
  -export([send_histogram/1]).
  
negative.code:             comm:send(Pid, {get_trace_reply, lists:reverse(Msgs)})
      end,
      State;
  on({cleanup, TraceId}, State) ->
      case lists:keytake(TraceId, 1, State) of
          {value, _Tuple, TupleList2} -> TupleList2;
          false                       -> State
      end.
  
  passed_state_new(TraceId, Logger) -> {TraceId, Logger}.
  passed_state_trace_id(State)      -> element(1, State).
  