class_docstr: A thread that batches requests to our file prepare API.
  
  Any number of threads may call prepare_async() in parallel. The PrepareBatcher thread
  will batch requests up and send them all to the backend at once.
code: def is_alive(self) -> bool:
      return self._thread.is_alive()
  
imports: import asyncio
  import functools
  import queue
  import threading
  import time
  from typing import TYPE_CHECKING, Callable, Dict, List, Mapping, NamedTuple, Optional, Sequence, Tuple, Union
label_desc: Use image node_id 8 for calling the StepPrepare obj's underlying member method code with example usage: obj.is_alive() and returns: self