anchor.diff:  
           {chunk, Data} ->
               send_chunk(Socket, Data),
  -            ?MODULE:chunk_loop(Socket, Req);
  +            ?MODULE:chunk_loop(Socket, Callback);
           {chunk, Data, From} ->
               case send_chunk(Socket, Data) of
                   ok ->
  
positive.code: %% user. We forward anything the user sends until the user sends an
  %% empty response, which signals that the connection should be
  %% closed. When the client closes the socket, the loop exits.
  start_chunk_loop(Socket, Req) ->
      inet:setopts(Socket, [{active, once}]),
      ?MODULE:chunk_loop(Socket, Req).
  
  chunk_loop(Socket, Req) ->
      receive
          {tcp_closed, Socket} ->
             ok;
  
          {chunk, <<>>} ->
              gen_tcp:send(Socket, <<"0\r\n\r\n">>),
  
negative.code:             send_response(Socket, 200, ResponseHeaders, <<"">>, Callback),
              Initial =:= <<"">> orelse send_chunk(Socket, Initial),
  
              start_chunk_loop(Socket, Callback),
  
              t(request_end),
              Mod:handle_event(request_complete,
  