Unity Project

reference
https://cardgames.io/yahtzee/

Library/PackageCache/com.unity.timeline@1.2.15/Editor/treeview/AnimationTrackKeyDataSource.cs

@@ -0,0 +1,25 @@
+using UnityEngine;
+using UnityEngine.Timeline;
+
+// Data sources for key overlays
+namespace UnityEditor.Timeline
+{
+    // Used for key overlays manipulators
+    class AnimationTrackKeyDataSource : BasePropertyKeyDataSource
+    {
+        readonly float m_TrackOffset;
+
+        protected override AnimationClip animationClip { get; }
+
+        public AnimationTrackKeyDataSource(AnimationTrack track)
+        {
+            animationClip = track != null ? track.infiniteClip : null;
+            m_TrackOffset = track != null ? (float)track.infiniteClipTimeOffset : 0.0f;
+        }
+
+        protected override float TransformKeyTime(float keyTime)
+        {
+            return keyTime + m_TrackOffset;
+        }
+    }
+}