class_docstr: Kafka event broker.
class_docstr_tok: ["Kafka","event","broker","."]
code: def _close(self) -> None:
      self._cancelled = True
      self._poll_thread.join()
  
imports: import asyncio
  import os
  import json
  import logging
  import structlog
  import threading
  from asyncio import AbstractEventLoop
  from typing import Any, Text, List, Optional, Union, Dict, TYPE_CHECKING
  import time
  from rasa.core.brokers.broker import EventBroker
  from rasa.core.exceptions import KafkaProducerInitializationError
  from rasa.shared.utils.io import DEFAULT_ENCODING
  from rasa.utils.endpoints import EndpointConfig
  import rasa.shared.utils.common
label_desc: Use image node_id 7 for calling the KafkaEventBroker obj's underlying member method code with example usage: obj._close() without return types