code: def summary_extra(self):
          
          out = {
              'errno': 0,
              'agent': request.headers.get('User-Agent', ''),
              'lang': request.headers.get('Accept-Language', ''),
              'method': request.method,
              'path': request.path,
          }
  
          # set the uid value to the current user ID
          user_id = self.user_id()
          if user_id is None:
              user_id = ''
          out['uid'] = user_id
  
          # the rid value to the current request ID
          request_id = g.get('_request_id', None)
          if request_id is not None:
              out['rid'] = request_id
  
          # and the t value to the time it took to render
          start_timestamp = g.get('_start_timestamp', None)
          if start_timestamp is not None:
              # Duration of request, in milliseconds.
              out['t'] = int(1000 * (time.time() - start_timestamp))
  
          return out
docs: Build the extra data for the summary logger.