code: def _init_polling(self):
          
          with self.lock:
              if not self.running:
                  return
  
              r = random.Random()
              delay = r.random() * self.refresh_interval
              self.channel.io_loop.call_later(
                  delay=delay, callback=self._delayed_polling)
              self.logger.info(
                  'Delaying throttling credit polling by %d sec', delay)
docs: Bootstrap polling for throttler.
  
          To avoid spiky traffic from throttler clients, we use a random delay
          before the first poll.