code: def _start_datathread(self) -> threading.Thread:
      return threading.Thread(
          target=self._data_main,
          name="ray_client_streaming_rpc",
          args=(),
          daemon=True,
      )
  
imports: import math
  import logging
  import queue
  import threading
  import warnings
  import grpc
  from collections import OrderedDict
  from typing import Any, Callable, Dict, TYPE_CHECKING, Optional, Union
  import ray.core.generated.ray_client_pb2
  import ray.core.generated.ray_client_pb2_grpc
  from ray.util.client.common import INT32_MAX, OBJECT_TRANSFER_CHUNK_SIZE, OBJECT_TRANSFER_WARNING_SIZE
  from ray.util.debug import log_once
label_desc: Use image node_id 3 for calling the DataClient obj's underlying member method code with example usage: obj._start_datathread() and returns: threading