def throttle_delay(self, node_id):
        """
        Return the number of milliseconds to wait until a broker is no longer throttled.
        When disconnected / connecting, returns 0.
        """
        conn = self._conns.get(node_id)
        if conn is None:
            return 0
        return conn.throttle_delay()

        Return the number of milliseconds to wait until a broker is no longer throttled.
        When disconnected / connecting, returns 0.
        
kafka/client_async.py