GoogleNavigation Framework Reference

GMSNavigationRouteCompletionHandler

typedef void (^GMSNavigationRouteCompletionHandler)(
    id<GMSNavigationRouteDescription> _Nullable, NSError *_Nullable)

Called when a route from the device’s location to the provided destination(s) is found, or fails to be found for a reason indicated by the GMSNavigationRouteDescription and NSError.

@related GMSNavigator