class_docstr: Timer to save elapsed time
docstr: elapsed time in seconds since instantiation or last restart call
docstr_tok: ["elapsed","time","in","seconds","since","instantiation","or","last","restart","call"]
code: def value(self) -> float:
      """
      elapsed time in seconds since instantiation or last restart call
      """
      return time.time() - self.start_time
  
imports: from __future__ import annotations
  import time
  import warnings
  from abc import ABC, abstractmethod
  from typing import Optional, Union
  from torch import Tensor
  from ..engine.distributed import reduce_value
label_desc: Use image node_id 2 for calling the Timer obj's underlying member method code with example usage: obj.value() and returns: unknown