How to tell when a Clip on a Track is done?

I'm messing with custom tracks and Playables, but ran into a snag, where I want to have a 'default' value, but then only if a Playable is there, it should use the Playables value.

I've found a way around it, which I guess is ok, but it just feels very hacky, and I was hoping there was a native solution that I just missed in the API. Please review what I'm using, and let me know if there is a better way to accomplish the same thing TY!

Code (CSharp):

1.  
2. using System;
3. using System.Collections;
4. using UnityEngine;
5. using UnityEngine.Playables;
6.  
7. public class MovementControlBehaviour : PlayableBehaviour
8. {
9.     public bool LockMovement;
10.  
11.     private Coroutine _destroy;
12.     private int _lastFrame;
13.     private Func<bool> _nextFrame = null;
14.  
15.     public override void OnPlayableCreate(Playable playable)
16.     {
17.         _lastFrame = Time.frameCount;
18.         _nextFrame = () => { return _lastFrame + 1 <= Time.frameCount; };
19.        
20.         base.OnPlayableCreate(playable);
21.     }
22.  
23.     public override void PrepareFrame(Playable playable, FrameData info)
24.     {
25.         _lastFrame = Time.frameCount;
26.         base.PrepareFrame(playable, info);
27.     }
28.  
29.     public override void ProcessFrame(Playable playable, FrameData info, object playerData)
30.     {
31.         InputData inputData = playerData as InputData;
32.         if (inputData != null)
33.         {
34.             inputData.MovementLocked = LockMovement;
35.             if (_destroy == null)
36.             {
37.                 _destroy = inputData.StartCoroutine(OnClipDestroyed(inputData));
38.             }
39.         }
40.     }
41.  
42.     public IEnumerator OnClipDestroyed(InputData inputData)
43.     {
44.         if (inputData == null)
45.         {
46.             yield break;
47.         }
48.  
49.         while (inputData.MovementLocked)
50.         {
51.             yield return new WaitUntil(_nextFrame);
52.             inputData.MovementLocked = false;
53.         }
54.         _destroy = null;
55.     }
56. }
57.  
58.