code: def tpu_client_timer_callback(
      timer_secs: float,
  ) -> xla_client.Client | None:
      def _log_warning():
          warnings.warn(
              f"TPU backend initialization is taking more than {timer_secs} seconds. "
              "Did you run your code on all TPU hosts? "
              "See https://jax.readthedocs.io/en/latest/multi_process.html "
              "for more information."
          )
  
      # Will log a warning after `timer_secs`.
      t = threading.Timer(timer_secs, _log_warning)
      t.start()
  
      try:
          client = xla_client.make_tpu_client(_get_tpu_library_path())
      finally:
          t.cancel()
  
      return client
  
imports: from __future__ import annotations
  from __future__ import annotations
  from collections.abc import Mapping
  import dataclasses
  from functools import lru_cache, partial
  import importlib
  import json
  import logging
  import os
  import pkgutil
  import platform
  import sys
  import threading
  from typing import Any, Callable, Union
  import warnings
  from jax._src import config
  from jax._src import distributed
  from jax._src import traceback_util
  from jax._src import util
  from jax._src import hardware_utils
  from jax._src.cloud_tpu_init import maybe_import_libtpu
  from jax._src.lib import cuda_versions
  from jax._src.lib import xla_client
  from jax._src.lib import xla_extension
  from jax._src.lib import xla_extension_version
label_desc: Use image node_id 3 for calling a global function with example usage: tpu_client_timer_callback(timer_secs) and returns: client