I have a question. It is not supportedExtensions in Model

hello~ . how are you!!

I have a model that is created with gltfpack that is opensource project.
Model is glb having KHR_mesh_quantization and KHR_texture_basisu.

I want to display on cesium, but I got error message.
I am using cesium version 1.78.
Can you give me the advice or hint?

An error occurred while rendering. Rendering has stopped.
RuntimeError: Unsupported glTF Extension: KHR_mesh_quantization

Error
at new RuntimeError (http://localhost:8080/cesium/Source/Core/RuntimeError.js:38:11)
at Object.ModelUtility.checkSupportedExtensions (http://localhost:8080/cesium/Source/Scene/ModelUtility.js:583:15)
at Model.update (http://localhost:8080/cesium/Source/Scene/Model.js:5215:22)
at PrimitiveCollection.update (http://localhost:8080/cesium/Source/Scene/PrimitiveCollection.js:377:19)
at updateAndRenderPrimitives (http://localhost:8080/cesium/Source/Scene/Scene.js:3374:21)
at executeCommandsInViewport (http://localhost:8080/cesium/Source/Scene/Scene.js:3149:5)
at Scene.updateAndExecuteCommands (http://localhost:8080/cesium/Source/Scene/Scene.js:2892:5)
at render (http://localhost:8080/cesium/Source/Scene/Scene.js:3768:9)
at tryAndCatchError (http://localhost:8080/cesium/Source/Scene/Scene.js:3787:5)
at Scene.render (http://localhost:8080/cesium/Source/Scene/Scene.js:3877:5)