@Nonnull
    @Override
    public MetadataMap provide(@Nonnull T id) {
        Objects.requireNonNull(id, "id");
        return this.cache.getUnchecked(id);
    }
A basic implementation of {@link MetadataRegistry} using a LoadingCache.

@param <T> the type
helper/src/main/java/me/lucko/helper/metadata/AbstractMetadataRegistry.java