Question How to implement custom track/signal with correct preview mode behaviour

Hi. I read several tutorials, documents about customizing Unity Timeline. But I can't find any information about preview mode reverting feature.

In example, Unity's ControlTrack instantiate Prefab instance while preview mode, and remove it when preview mode is end. How to implement this cleaning up behaviour for custom track/signal?

https://forum.unity.com/threads/how...reset-to-previous-state-after-preview.666892/ explains how to revert bound object itself, but can't be used for reverting instantiated artifacts.