private static class TransformCache {
        private final ConcurrentHashMap<CacheKey, List<CachedVariant>> cache = new ConcurrentHashMap<>();
        private final BiFunction<List<ImmutableAttributes>, ImmutableAttributes, List<CachedVariant>> action;

        public TransformCache(BiFunction<List<ImmutableAttributes>, ImmutableAttributes, List<CachedVariant>> action) {
            this.action = action;
        }