What does Unity.Animation.AddRef() do?

Code (CSharp):

1. namespace Unity.Animation
2. {
3.     public abstract class GraphSystemBase<TGraphTag> : JobComponentSystem, IGraphSystem<TGraphTag> where TGraphTag : struct, IGraphTag
4.     {
5.         protected GraphSystemBase();
6.  
7.         public NodeSet Set { get; }
8.         public int RefCount { get; }
9.         public TGraphTag Tag { get; }
10.  
11.         public void AddRef();
12.         public void RemoveRef();
13.         protected override void OnCreate();
14.         protected override JobHandle OnUpdate(JobHandle inputDeps);
15.         protected internal override void OnCreateForCompiler();
16.     }
17. }

I see it used in the example code.

Code (CSharp):

1.     protected override void OnCreate()
2.     {
3.         base.OnCreate();
4.         m_GraphSystem  = World.GetOrCreateSystem<TAnimationGraph>();
5.         m_GraphSystem.AddRef();
6.         m_GraphSystem.Set.RendererModel  = NodeSet.RenderExecutionModel.Islands;

 

A comment from here: https://github.com/Unity-Technologi...Blendshapes/Blendshapes_ClipPlayer.cs#L53-L54

Code (CSharp):

1. // Increase the reference count on the graph system so it knows
2. // that we want to use it.