docs: def warn(msg: str, resource: Optional['Resource'] = None, stream_id: Optional[int] = None) -> None:
      """
      Logs a message to the Pulumi CLI's warning channel, associating it with a resource
      and stream_id if provided.
  
      :param str msg: The message to send to the Pulumi CLI.
      :param Optional[Resource] resource: If provided, associate this message with the given resource in the Pulumi CLI.
      :param Optional[int] stream_id: If provided, associate this message with a stream of other messages.
      """
      engine = get_engine()
      if engine is not None:
          _log(engine, engine_pb2.WARNING, msg, resource, stream_id)
      else:
          print("warning: " + msg, file=sys.stderr)