code: def start(self, name: str, rank: int):
      # TODO : add lock to prevent conflict
      torch.cuda.synchronize()
      start_time = time.time()
      self.temp_event = Event(start_time, None, name, rank)
  
imports: import atexit
  import json
  import os
  import shutil
  import time
  from typing import Dict, List
  import matplotlib.colors
  import matplotlib.pyplot
  import torch
  import torch.distributed
label_desc: Use image node_id 2 for calling the Recorder obj's underlying member method code with example usage: obj.start(name, rank) without return types