docs: def respond(self):
          """Call the gateway and write its iterable output."""
          mrbs = self.server.max_request_body_size
          if self.chunked_read:
              self.rfile = ChunkedRFile(self.conn.rfile, mrbs)
          else:
              cl = int(self.inheaders.get("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()
          
          if (self.ready and not self.sent_headers):
              self.sent_headers = True
              self.send_headers()
          if self.chunked_write:
              self.conn.wfile.sendall("0\r\n\r\n")