suppose there is a planned route on the map, and a car is driving along the route, and when an emergency occurs, the road ahead is congested, and the background needs to re-send rescheduled path information to the front end, but the transmission of the path information takes a period of time, and the length of this period of time is unknown. How should the front end handle this period of time to make a smooth transition from the original path to the new path.