docs: @SuppressWarnings("unchecked")
    public final LongCache<V> buildForLongKey() {
      Cache2kConfiguration<K,V> cfg = config();
      if (cfg.getKeyType().getType() != Long.class) {
        throw new IllegalArgumentException("Long key type expected, was: " + cfg.getKeyType());
      }
      return (LongCache<V>) CacheManager.PROVIDER.createCache(manager, config());
    }