code: public void addRoute(DirectionsRoute directionsRoute) {
      List<DirectionsRoute> routes = new ArrayList<>();
      routes.add(directionsRoute);
      addRoutes(routes);
    }
docs: Allows adding a single primary route for the user to traverse along. No alternative routes will
  be drawn on top of the map.
  
  @param directionsRoute the directions route which you'd like to display on the map
  @since 0.4.0