Animating shadow path using UIViewPropertyAnimator

I'm trying to animate a layer's shadowPath property using UIViewPropertyAnimator but it looks like it's getting instantaneously set (instead of animating or being able to set the fraction complete on the animation.)

Is there an alternative way to do this?

view.layer.shadowPath = UIBezierPath(roundedRect: .init(origin: .zero, size: .init(width: 100, height: 100)), cornerRadius: 12).cgPath

let animator = UIViewPropertyAnimator(duration: 2.0, curve: .easeInOut) {
  view.layer.shadowPath = UIBezierPath(roundedRect: .init(origin: .zero, size: .init(width: 200, height: 200)), cornerRadius: 12).cgPath
}
animator.scrubsLinearly = false
animator.pauseAnimation()
animator.fractionComplete = 0