code: def update(self):
      self.count += 1
  
      if self.last_update == 0:
          self.last_update = perf_counter()
          self.startTimer(self.interval)
  
file_path: pyqtgraph/pyqtgraph/examples/utils.py
imports: from argparse import Namespace
  from collections import OrderedDict
  from time import perf_counter
  from pyqtgraph.Qt import QtCore
label_desc: Use image node_id 2 for calling the FrameCounter obj's underlying member method code with example usage: obj.update() without return types