class_docstr: Base Rate Limiter class for both sync and async versions.
code: def _clock(self):  # pragma: no cover
      return default_timer()
  
imports: import asyncio
  import inspect
  import threading
  from itertools import chain, count
  from time import sleep
  from timeit import default_timer
  from geopy.exc import GeocoderServiceError
  from geopy.util import logger
label_desc: Use image node_id 2 for calling the BaseRateLimiter obj's underlying member method code with example usage: obj._clock() and returns: default_timer