code: def _send_message(self, record: "pb.Record") -> None:
      raise NotImplementedError
  
imports: import logging
  import threading
  import uuid
  from abc import abstractmethod
  from typing import TYPE_CHECKING, Dict, Optional
  from ..lib import mailbox, tracelog
  from .message_future import MessageFuture
label_desc: Use image node_id 3 for calling the MessageRouter obj's underlying member method code with example usage: obj._send_message(record) without return types