我使用的是Unity 2021.3.22f1和AR Foundation 4.2.7版本。我已经在场景中添加了AR Session和AR Session Origin，以及AR Tracked Image Manager作为AR Session Origin的组件。
我想创建一个MutableRuntimeReferenceImageLibrary，它在运行时动态地添加包含在项目文件夹中的图像。
我写了这段代码：

using System.Collections.Generic;
using UnityEngine;
using UnityEngine.XR.ARFoundation;
using UnityEngine.XR.ARSubsystems;

public class ImageLibraryManager : MonoBehaviour
{
    public ARTrackedImageManager trackedImageManager;
    public string imageFolderPath;

    void Start()
    {
        // Create a list to hold XRReferenceImage objects
        var imageList = new List<XRReferenceImage>();

        // Get the files in the image folder
        var imageFiles = System.IO.Directory.GetFiles(imageFolderPath);

        // Loop through the image files and add them to the list
        foreach (var imageFile in imageFiles)
        {
            // Load the image from the file
            var imageBytes = System.IO.File.ReadAllBytes(imageFile);
            var texture = new Texture2D(2, 2);
            texture.LoadImage(imageBytes);

            var newGuid = System.Guid.NewGuid();
            var guidBytes = newGuid.ToByteArray();
            var image = new XRReferenceImage(
                // Use a new guid for each image
                new SerializableGuid(
                    (ulong)(guidBytes[3] << 24 | guidBytes[2] << 16 | guidBytes[1] << 8 | guidBytes[0]),
                    (ulong)(guidBytes[7] << 24 | guidBytes[6] << 16 | guidBytes[5] << 8 | guidBytes[4])
                ),
                // Use an empty guid for the second parameter
                SerializableGuid.empty,
                // Set the size of the image in meters
                new Vector2(texture.width, texture.height) / 1000f,
                // Set the name of the image
                System.IO.Path.GetFileNameWithoutExtension(imageFile),
                // Set the texture of the image
                texture
            );

            imageList.Add(image);
        }

        // Create a new MutableRuntimeReferenceImageLibrary and assign it to the ARTrackedImageManager
        var imageLibrary = trackedImageManager.CreateRuntimeLibrary() as MutableRuntimeReferenceImageLibrary;
        foreach (var image in imageList)
        {
            // Add each image to the image library
            imageLibrary.AddReferenceImage(image);
        }
        trackedImageManager.referenceLibrary = imageLibrary;
    }
}

然而，这给了我这个错误：Assets/ImageLibraryManager.cs(53,26): error CS1061: 'MutableRuntimeReferenceImageLibrary' does not contain a definition for 'AddReferenceImage' and no accessible extension method 'AddReferenceImage' accepting a first argument of type 'MutableRuntimeReferenceImageLibrary' could be found (are you missing a using directive or an assembly reference?)
我已经尝试过其他方法，如“添加”或“添加图像”，但它总是给我同样的错误。
你能帮助我解决我的问题，并创建这种类型的MutableRuntimeReferenceImageLibrary吗？
谢谢你