class_docstr: Measure elapesed time via 'with' context.
code: def __exit__(self, etype, value, traceback):
      elapsed_time = time.time() - self.t
      # used to format the time, returning a readable string.
      stime = time.strftime("%H:%M:%S", time.gmtime(elapsed_time))
      print(f"LEAVE: {self.msg} [{stime}]")
  
file_path: BigDL/python/friesian/example/recall/utils.py
imports: import time
  import os
  import multiprocessing
label_desc: Use image node_id 3 for calling the StopWatch obj's underlying member method code with example usage: obj.__exit__(etype, value, traceback) without return types