Sceneform SDK for Android was open sourced and archived (github.com/google-ar/sceneform-android-sdk) with version 1.16.0.
This site (developers.google.com/sceneform) serves as the documentation archive for the previous version, Sceneform SDK for Android 1.15.0.
Do not use version 1.17.0 of the Sceneform Maven artifacts.
The 1.17.1 Maven artifacts can be used. Other than the version, however, the 1.17.1 artifacts are identical to the 1.15.0 artifacts.

TwistGesture.OnGestureEventListener

Page Summary

TwistGesture.OnGestureEventListener defines callbacks for reacting to a TwistGesture.
It inherits methods from BaseGesture.OnGestureEventListener for handling gesture updates and completion.
The key methods include onFinished and onUpdated, triggered when a twist gesture ends and during its progress, respectively.

public static interface TwistGesture.OnGestureEventListener

Interface definition for callbacks to be invoked by a TwistGesture.

From interface com.google.ar.sceneform.ux.BaseGesture.OnGestureEventListener

abstract void	onFinished(TwistGesture gesture)
abstract void	onUpdated(TwistGesture gesture)