docstr: Process events related to the spawned Tk application window.
  First, update the Tk instance, then call `_delayed_update`
  on every created Toplevel (to force a redraw), and process some Tkinter
  GUI events by calling the Tk.mainloop and immediately exiting.
code: def _vispy_process_events(self):
      """Process events related to the spawned Tk application window.
      First, update the Tk instance, then call `_delayed_update`
      on every created Toplevel (to force a redraw), and process some Tkinter
      GUI events by calling the Tk.mainloop and immediately exiting.
      """
      # Update idle tasks first (probably not required)
      app = self._vispy_get_native_app()
      app.update_idletasks()
  
      # Update every active Canvas window
      for c in _TkInstanceManager.get_canvasses():
          c._delayed_update()
  
      # Process some events in the main Tkinter event loop
      # And quit so we can continue elsewhere (call blocks normally)
      app.after(0, lambda: app.quit())
      app.mainloop()
  
imports: from __future__ import division
  from time import sleep
  import warnings
  from ..base import BaseApplicationBackend, BaseCanvasBackend, BaseTimerBackend
  from ...util import keys
  from ...util.ptime import time
  from ...gloo import gl
label_desc: Use image node_id 2 for calling the ApplicationBackend obj's underlying member method code with example usage: obj._vispy_process_events() without return types