anchor.diff:  tpl([]) ->
       ok.
   
  -tracer({trace,_,call,{logger_disk_log_h,handle_cast,[Op|_]}},
  +tracer({trace,_,call,{logger_disk_log_h,handle_cast,[Op|_]},Caller},
          {Pid,[{Mod,Func,Op}|Expected]}) ->
  -    maybe_tracer_done(Pid,Expected,{Mod,Func,Op});
  -tracer({trace,_,call,{Mod=disk_log,Func=blog,[_,Data]}}, {Pid,[{Mod,Func,Data}|Expected]}) ->
  -    maybe_tracer_done(Pid,Expected,{Mod,Func,Data});
  -tracer({trace,_,call,{Mod,Func,_}}, {Pid,[{Mod,Func}|Expected]}) ->
  -    maybe_tracer_done(Pid,Expected,{Mod,Func});
  -tracer({trace,_,call,Call}, {Pid,Expected}) ->
  -    ct:log("Tracer got unexpected: ~p~nExpected: ~p~n",[Call,Expected]),
  +    maybe_tracer_done(Pid,Expected,{Mod,Func,Op},Caller);
  +tracer({trace,_,call,{Mod=disk_log,Func=blog,[_,Data]},Caller}, {Pid,[{Mod,Func,Data}|Expected]}) ->
  +    maybe_tracer_done(Pid,Expected,{Mod,Func,Data},Caller);
  +tracer({trace,_,call,{Mod,Func,_},Caller}, {Pid,[{Mod,Func}|Expected]}) ->
  +    maybe_tracer_done(Pid,Expected,{Mod,Func},Caller);
  +tracer({trace,_,call,Call,Caller}, {Pid,Expected}) ->
  +    ct:log("Tracer got unexpected: ~p~nCaller: ~p~nExpected: ~p~n",[Call,Caller,Expected]),
       Pid ! {tracer_got_unexpected,Call,Expected},
       {Pid,Expected}.
   
  -maybe_tracer_done(Pid,[],Got) ->
  -    ct:log("Tracer got: ~p~n",[Got]),
  +maybe_tracer_done(Pid,[],Got,Caller) ->
  +    ct:log("Tracer got: ~p~nCaller: ~p~n",[Got,Caller]),
       Pid ! tracer_done;
  -maybe_tracer_done(Pid,Expected,Got) ->
  -    ct:log("Tracer got: ~p~n",[Got]),
  +maybe_tracer_done(Pid,Expected,Got,Caller) ->
  +    ct:log("Tracer got: ~p~nCaller: ~p~n",[Got,Caller]),
       {Pid,Expected}.
   
   check_tracer(T) ->
  
positive.code:     ok.
  
  tpl([{M,F,A}|Trace]) ->
      {ok,Match} = dbg:tpl(M,F,A,[]),
      case lists:keyfind(matched,1,Match) of
          {_,_,1} ->
              ok;
  
negative.code:                               formatter=>{?MODULE,nl}}),
  
      start_tracer([{disk_log,blog,2},
                    {logger_disk_log_h,disk_log_sync,2}],
                   [{disk_log,blog,<<"first\n">>},
                    {logger_disk_log_h,disk_log_sync}]),
  
      logger:notice("first", ?domain),
      %% wait for automatic disk_log_sync
      check_tracer(?FILESYNC_REPEAT_INTERVAL*2),
      
      %% check that if there's no repeated disk_log_sync active,
      %% a disk_log_sync is still performed when handler goes idle
      {ok,#{config := HConfig}} = logger:get_handler_config(?MODULE),
  