code: public void startNavigation(@NonNull DirectionsRoute directionsRoute, @NonNull DirectionsRouteType routeType) {
      startNavigationWith(directionsRoute, routeType);
    }
docs: Calling this method with {@link DirectionsRouteType#NEW_ROUTE} begins a new navigation session using the
  provided directions route.  If called with {@link DirectionsRouteType#FRESH_ROUTE}, only leg annotation data
  will be update - can be used with {@link RouteRefresh}.
  
  @param directionsRoute a {@link DirectionsRoute} that makes up the path your user should
  traverse along
  @param routeType       either new or fresh to determine what data navigation should consider
  @see MapboxNavigation#startNavigation(DirectionsRoute)