code: def respond(self):
          
          mrbs = self.server.max_request_body_size
          if self.chunked_read:
              self.rfile = ChunkedRFile(self.conn.rfile, mrbs)
          else:
              cl = int(self.inheaders.get(b'Content-Length', 0))
              if mrbs and mrbs < cl:
                  if not self.sent_headers:
                      self.simple_response(
                          '413 Request Entity Too Large',
                          'The entity sent with the request exceeds the '
                          'maximum allowed bytes.',
                      )
                  return
              self.rfile = KnownLengthRFile(self.conn.rfile, cl)
  
          self.server.gateway(self).respond()
          self.ready and self.ensure_headers_sent()
  
          if self.chunked_write:
              self.conn.wfile.write(b'0\r\n\r\n')
docs: Call the gateway and write its iterable output.