code: def __init__(self, stream):
      self.start_ = torch.cuda.Event(enable_timing=True)
      self.stop_ = torch.cuda.Event(enable_timing=True)
      self.stream_ = stream
  
imports: import itertools
  import unittest
  import torch
label_desc: Use image node_id 1 to create a new GPUTimer object  with example: obj = GPUTimer(stream)