Android SDK - Background scanning


I am reading the official docs from GitHub - Estimote/Android-Proximity-SDK: Estimote Proximity SDK for Android

There you say to build observer with withScannerInForegroundService() for background scanning.
But later on you propose to use ProximityTriggerBuilder to build ProximityTrigger where you also pass notification.

Assume I am running app only on devices with Android 8+.
What should I use for background scanning with events. If I set both I have two sticky notificaions.