code: def output(self, stream, disabletransferencoding = None):
          
          if self._sendHeaders:
              raise HttpProtocolException('Cannot modify response, headers already sent')
          self.outputstream = stream
          try:
              content_length = len(stream)
          except Exception:
              pass
          else:
              self.header(b'Content-Length', str(content_length).encode('ascii'))
          if disabletransferencoding is not None:
              self.disabledeflate = disabletransferencoding
          self._startResponse()
docs: Set output stream and send response immediately