<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _spawn_background_rendering(self, rate=5.0):
 """ Spawns a thread that updates the render window. Sometimes directly modifiying object data doesn't trigger Modified() and upstream objects won't be updated. This ensures the render window stays updated without consuming too many resources. """

        self.render_trigger.connect(self.ren_win.Render)
        twait = rate**-1

        def render():
            while self.active:
                time.sleep(twait)
                self._render()

        self.render_thread = Thread(target=render)
        self.render_thread.start()