Interface AnimationTrackLike

A track with its value type erased — what AnimationClip stores and what the mixer consumes.

A clip's tracks are heterogeneous (a position track next to a color track next to a Boolean track), so the array element type cannot name one T. This interface is the honest erasure: every AnimationTrack<T> satisfies it, and a consumer holding one works through AnimationTrackLike.adapter — whose ValueAdapter.mutatesInPlace tells it how to treat the value — exactly as PropertyBinding does.