anchor.diff:  -spec init([]) -> {ok, #state{}}.
   init([]) ->
       lager:info("Test orchestrator started on node: ~p", [node()]),
  -    {ok, #state{trace=[]}}.
  +
  +    %% Open trace file for writing.
  +    case file:open("/tmp/partisan.trace", [write]) of
  +        {ok, File} ->
  +            {ok, #state{trace=[], file=File}};
  +        {error, Error} ->
  +            lager:error("couldn't open trace file for writing."),
  +            {stop, Error}
  +    end.
   
   %% @private
   -spec handle_call(term(), {pid(), term()}, #state{}) ->
  
positive.code:         Count + 1
      end, 1, Trace),
  
      {reply, ok, State};
  handle_call(Msg, _From, State) ->
      lager:warning("Unhandled call messages at module ~p: ~p", [?MODULE, Msg]),
  
negative.code: handle_call({identify, Identifier}, _From, State) ->
      lager:info("~p: identifying trace: ~p", [?MODULE, Identifier]),
      {reply, ok, State#state{identifier=Identifier}};
  handle_call(print, _From, #state{trace=Trace, file=File}=State) ->
      lager:info("~p: printing trace", [?MODULE]),
  
      lists:foldl(fun({Type, Message}, Count) ->
  