anchor.diff:      case Answer of
           true ->
               {ok, cowboy_req:reply(200, #{
  -                <<"content-type">> => <<"text/plain; charset=utf-8">>
  +                <<"content-type">> => <<"text/plain; charset=utf-8">>,
  +                <<"Access-Control-Allow-Origin">> => <<"*">>
               }, format_out(Event, Out), Req), State};
           false ->
               cowboy_req:reply(409, Req)
  
positive.code:     {ok, cowboy_req:reply(400, #{}, <<"Missing body.">>, Req), State};
  maybe_process(Req, State, <<"GET">>, Path, _) ->
      process_get(Req, State, Path);
  maybe_process(Req, _, _, _, _) ->
      %% Method not allowed.
      cowboy_req:reply(405, Req).
  
negative.code:         {Date, From, FirstChunk} ->
              Req1 = cowboy_req:stream_reply(200, #{
                  <<"Content-Type">> => <<"application/octet-stream">>,
                  <<"Access-Control-Allow-Origin">> => <<"*">>,
                  <<"From">> => From,
                  <<"ETag">> => <<"\"", (integer_to_binary(Date))/binary, "\"">>
              }, Req),
  