class_docstr: A time stat for logging the elapsed time of code running
  
  Example:
      time_stat = TimeStat()
      with time_stat:
          // some code
      print(time_stat.mean)
code: def __init__(self, window_size=1):
      self.time_samples = WindowStat(window_size)
      self._start_time = None
  
file_path: PARL/parl/utils/time_stat.py
imports: import time
  from parl.utils.window_stat import WindowStat
label_desc: Use image node_id 1 to create a new TimeStat object from inherited base classes: object with example: obj = TimeStat(window_size)