I try to implement plane detection in my AR experience.
I have a subclass of ARSCNView with an ARSCNViewDelegate extension.
My cameraDidChangeTrackingState delegate method is called. However, I've never ONCE see my renderer(_:didAdd node:, for anchor:) method being called. Any idea?
class ARView: ARSCNView {
    override init(frame: CGRect, options: [String : Any]? = nil) {
        super.init(frame: frame, options: options)
        let sessionConfig = ARWorldTrackingConfiguration()
        sessionConfig.planeDetection = [.horizontal]
        self.session.run(sessionConfig)
        self.delegate = self
    }
}
extension ARView: ARSCNViewDelegate{
    func renderer(_ renderer: SCNSceneRenderer, didAdd node: SCNNode, for anchor: ARAnchor) {
    //add childNodes to the node here....
    //but, this method doesn't get called
    }
}
EDIT: I can find ARPlaneAnchors session(_ session: ARSession, didAdd anchors: [ARAnchor]) but I am not sure if I should use this one, because in most (also Apples) examples they add objects to the node of the anchor like shown in my code above. Or do I have to trigger that didAdd node:, for anchor method myself?