internal static extern IntPtr AddClass(IntPtr handle, string classId, WidgetiInstanceLifecycleCallbacks callback, IntPtr userData);
internal static extern IntPtr CreateClass(WidgetiInstanceLifecycleCallbacks callback, IntPtr userData);
internal static extern IntPtr AddClass(IntPtr handle, string classId, WidgetiInstanceLifecycleCallbacks callback, IntPtr userData);
internal static extern IntPtr CreateClass(WidgetiInstanceLifecycleCallbacks callback, IntPtr userData);