code: def on_timer_event(self, event):
      if self._timer.running:
          self.program["u_global_time"] += event.dt
      self.update()
  
file_path: vispy/examples/demo/gloo/high_frequency.py
imports: from vispy import gloo, app, keys
label_desc: Use image node_id 4 for calling the Canvas obj's underlying member method code with example usage: obj.on_timer_event(event) without return types