public override Playable CreateTrackMixer(PlayableGraph graph, GameObject go, int inputCount)
                {
                    ScriptPlayable <Spine3DAnimatorChannelTrackMixer> playable = TimelineUtils.CreateTrackMixer <Spine3DAnimatorChannelTrackMixer>(this, graph, go, inputCount);
                    Spine3DAnimatorTrack parentTrack = this.parent as Spine3DAnimatorTrack;

                    if (parentTrack != null)
                    {
                        Spine3DAnimatorTrackMixer parentMixer = TimelineUtils.GetTrackMixer <Spine3DAnimatorTrackMixer>(graph, parentTrack);

                        if (parentMixer != null)
                        {
                            Spine3DAnimatorChannelTrackMixer mixer = playable.GetBehaviour();
                            mixer.Init(parentMixer);

                            IEnumerable <TimelineClip> clips = GetClips();

                            foreach (TimelineClip clip in clips)
                            {
                                Spine3DAnimationClipAsset animationClip = clip.asset as Spine3DAnimationClipAsset;

                                if (animationClip != null)
                                {
                                    clip.displayName = animationClip._animationId;
                                    animationClip.SetParentTrack(parentTrack);
                                }
                            }
                        }
                    }

                    return(playable);
                }
                protected override void OnCreateClip(TimelineClip clip)
                {
                    Spine3DAnimatorTrack parentTrack = this.parent as Spine3DAnimatorTrack;

                    if (parentTrack != null)
                    {
                        Spine3DAnimationClipAsset animationClip = clip.asset as Spine3DAnimationClipAsset;

                        if (animationClip != null)
                        {
                            animationClip.SetParentTrack(parentTrack);
                        }
                    }
                }