code: def start(self) -> None:
      self._thread.start()
      if self._async_executor:
          self._async_executor.start()
  
imports: import asyncio
  import concurrent.futures
  import logging
  import queue
  import sys
  import threading
  from typing import TYPE_CHECKING, Awaitable, Callable, MutableMapping, MutableSequence, MutableSet, NamedTuple, Optional, Union
  from wandb.errors.term import termerror
  from wandb.filesync import upload_job
  from wandb.sdk.lib.paths import LogicalPath
label_desc: Use image node_id 12 for calling the StepUpload obj's underlying member method code with example usage: obj.start() without return types