How does the imported gltf model modify the material to display the vertex color in geometry?

[mlt131220]

What happened?

const modelPrimitive = await Cesium.Model.fromGltfAsync({
                    id: generateUUID(),
                    url: url,
                    modelMatrix: modelMatrix,
                    ...Object.assign({
                        show: true,
                        scale: 1,
                        shadows: Cesium.ShadowMode.ENABLED,
                        minimumPixelSize: 128,
                        maximumScale: 20000,
                        allowPicking: true,
                        customShader: undefined,
                        // 确定模型相对于地形的绘制方式
                        heightReference: Cesium.HeightReference.NONE,
                        // 指定该模型将在距相机多远处显示的条件
                        distanceDisplayCondition: new Cesium.DistanceDisplayCondition(0.0, 300.0),
                        // 一种与模型渲染颜色混合的颜色
                        color: Cesium.Color.fromCssColorString("rgba(255,255,255,1)"),
                        // colorBlendMode:  Cesium.ColorBlendMode.HIGHLIGHT, // 使用MIX模式以混合顶点颜色
                        colorBlendMode: Cesium.ColorBlendMode.MIX, // 使用MIX模式以混合顶点颜色
                        // 当colorBlendMode为MIX时，用于确定颜色强度的值
                        colorBlendAmount: 0.0,
                        // 模型阴影时的浅色。如果未定义，则使用场景的光照颜色代替
                        lightColor: undefined,
                    }, options),
                    gltfCallback: gltf => {
                        animations = gltf.animations;

                        gltf.nodes.forEach(node => {
                            extras.set(node.name, node.extras);
                        })
                    }
                });

                this.viewer.scene.primitives.add(modelPrimitive);

                modelPrimitive.name = options.name || "Model";
                modelPrimitive.type = options.modelType || "Model";
                modelPrimitive.readyEvent.addEventListener(() => {
                    // extras数据添加至对应node中
                    extras.forEach((value, key) => {
                        const _node = modelPrimitive.getNode(key)._runtimeNode.node;
                        if (!_node) return;
                        _node.extras = value;
                    })

                    resolve({ model: modelPrimitive, animations, extras });
                });

I use this method to import a gltf model whose geometry contains position, normal, color, and I need to replace the displayed material with a vertex color after loading, and then switch from the vertex color to the original pbr material.
Problem: The vertex color cannot be displayed by replacing the material.

Something like this in threejs:

Reproduction steps

...

Sandcastle example

No response

Environment

Browser: Edge
CesiumJS Version: 1.123
Operating System: windows11