Hello, I am writing the class to customize fade-in effect by referencing SkeletonRenderTextureFadeout.

using UnityEngine;
using Spine.Unity;

[RequireComponent(typeof(SkeletonRenderTextureBase))]
public class SkeletonRenderTextureFade : MonoBehaviour {
	SkeletonRenderTextureBase skeletonRenderTexture;

}

However, the editor says SkeletonRenderTextureBase could not be found.
The SkeletonRenderTextureFadeout itself works well though.