Record the time at which request ordering started.

def requestUnOrdered(self, key: str):
        """
        Record the time at which request ordering started.
        """
        now = time.perf_counter()
        if self.acc_monitor:
            self.acc_monitor.update_time(now)
            self.acc_monitor.request_received(key)
        self.requestTracker.start(key, now)