anchor.diff:  %% response.
   execute_callback(Req, {Mod, Args}) ->
       try Mod:handle(Req, Args) of
  -        {ok, Headers, Body}       -> {200, Headers, Body};
  -        {ok, Body}                -> {200, [], Body};
  -        {HttpCode, Headers, Body} -> {HttpCode, Headers, Body};
  -        {chunk, Headers}          -> {chunk, Headers};
  -        {HttpCode, Body}          -> {HttpCode, [], Body}
  +        {ok, Headers, Body}       -> {response, 200, Headers, Body};
  +        {ok, Body}                -> {response, 200, [], Body};
  +        {chunk, Headers}          -> {chunk, Headers, <<"">>};
  +        {chunk, Headers, Initial} -> {chunk, Headers, Initial};
  +        {HttpCode, Headers, Body} -> {response, HttpCode, Headers, Body};
  +        {HttpCode, Body}          -> {response, HttpCode, [], Body}
       catch
           throw:{ResponseCode, Headers, Body} when is_integer(ResponseCode) ->
               {ResponseCode, Headers, Body};
  
positive.code:                     ok
              end;
  
          {chunk, UserHeaders} ->
              t(user_end),
  
              ResponseHeaders = [{<<"Transfer-Encoding">>, <<"chunked">>},
                                 connection(Req, UserHeaders)
                                 | UserHeaders],
              send_response(Socket, 200, ResponseHeaders, <<>>, Callback),
  
              chunk_loop(Socket, Req),
  
  
negative.code: 
      t(user_start),
      case execute_callback(Req, Callback) of
          {response, ResponseCode, UserHeaders, UserBody} ->
              t(user_end),
  
              ResponseHeaders = [
  