Will initialize the route line related layers. Other calls in this class will initialize the layers if they have not yet been initialized. If you have a use case for initializing the layers in advance of any API calls this method may be used.
Each Layer added to the map by this class is a persistent layer - it will survive style changes. This means that if the data has not changed, it does not have to be manually redrawn after a style change. See Style.addPersistentStyleLayer.
a valid Style instance