class_docstr: Timer context manager to get the elapsed time for a code block.
  
  Example:
      .. code-block:: python
  
          with Timer() as timer:
              do_something()
          elapsed_time = timer.elapsed_time
class_docstr_tok: ["Timer","context","manager","to","get","the","elapsed","time","for","a","code","block",".","Example",":","..","code-block",":",":","python","with","Timer","(",")","as","timer",":","do_something","(",")","elapsed_time","=","timer.elapsed_time"]
code: def __exit__(self, *args, **kwargs):
      self.elapsed_time = time.perf_counter() - self.start
  
imports: import collections.abc
  import contextlib
  import json
  import logging
  import os
  import time
  from functools import partial
  from typing import Any, Dict, List, Optional, Tuple, Union
  import numpy
  import torch
  import torch.nn
  from classy_vision.generic.distributed_util import broadcast_object, is_primary
  from fvcore.common.file_io import PathManager
label_desc: Use image node_id 3 for calling the Timer obj's underlying member method code with example usage: obj.__exit__() without return types