onAttached
Signals that the mapboxNavigation instance is ready for use. Use this function to register mapboxNavigation observers, such as MapboxNavigation.registerRoutesObserver.
After you have registered an observer through MapboxNavigationApp.registerObserver, the onAttached will be called when at least one LifecycleOwner that has been attached to MapboxNavigationApp.attach and is at least in the Lifecycle.State.STARTED state.
Parameters
mapboxNavigation
instance that is being attached.