docs: private void deliverCacheUpdate(SlotReference slot, MetadataCache cache) {
          for (final MetadataCacheListener listener : getCacheListeners()) {
              try {
                  if (cache == null) {
                      listener.cacheDetached(slot);
                  } else {
                      listener.cacheAttached(slot, cache);
                  }
              } catch (Throwable t) {
                  logger.warn("Problem delivering metadata cache update to listener", t);
              }
          }
      }