class_docstr: Measure elapesed time via 'with' context.
code: def __enter__(self):
      self.t = time.time()
      print(f"ENTER: {self.msg}")
      return self.t
  
file_path: BigDL/python/friesian/example/recall/utils.py
imports: import time
  import os
  import multiprocessing
label_desc: Use image node_id 2 for calling the StopWatch obj's underlying member method code with example usage: obj.__enter__() and returns: self