anchor.diff:      {ok, ResReq} =
           case xprof_tracer_handler:capture_stop(MFA) of
               ok ->
  -                cowboy_req:reply(204, Req);
  +                cowboy_req:reply(204, ?HDR_NO_CONTENT, Req);
               {error, not_found} ->
                   cowboy_req:reply(404, Req)
           end,
  
positive.code:     lager:info("Stopping monitoring via web on ~w:~w/~w~n",[M,F,A]),
  
      xprof_tracer:demonitor(MFA),
      {ok, ResReq} = cowboy_req:reply(204, Req),
      {ok, ResReq, State};
  
  handle_req(<<"mon_get_all">>, Req, State) ->
  
negative.code: -export([init/3,handle/2,terminate/3]).
  
  -behavior(cowboy_http_handler).
  
  %% In case an XHR receives no content with no content-type Firefox will emit
  %% the following error: "XML Parsing Error: no root element found..."
  %% As a workaround always return a content-type of octet-stream with
  %% 204 No Content responses
  -define(HDR_NO_CONTENT, [{<<"Content-type">>, <<"application/octet-stream">>}]).
  
  %% Cowboy callbacks
  
  