var bytes = File.ReadAllBytes(file);
VRMMetaObject meta;
using(var metaLoader = new VRM.QuickMetaLoader.MetaLoader(bytes, false))
{
	meta = metaLoader.Read();
}

var bytes = File.ReadAllBytes(file);
using(var metaLoader = new VRM.QuickMetaLoader.MetaLoader(bytes))
{
	VRMMetaObject meta = metaLoader.Read();

	// some process...

	Texture2D thumbnail = metaLoader.LoadThumbnail();
}

using(var metaLoader = new JobMetaLoader(file, preloadThumbnail: true))
{
	VRMMetaObject meta = metaLoader.Read();

	// some process...

	meta.Thumbnail =  metaLoader.LoadThumbnail();
}