docs: void attachMetadataCacheInternal(SlotReference slot, MetadataCache cache) {
          MetadataCache oldCache = metadataCacheFiles.put(slot, cache);
          if (oldCache != null) {
              try {
                  oldCache.close();
              } catch (IOException e) {
                  logger.error("Problem closing previous metadata cache", e);
              }
          }
  
          deliverCacheUpdate(slot, cache);
      }