code: private static <K, V> List<V> aggregateCacheValues(Map<K, CacheValue<V>> map) {
      List<V> values = new ArrayList<>(map.size());
      for (Map.Entry<K, CacheValue<V>> entry : map.entrySet()) {
        values.add(entry.getValue().getValue());
      }
      return values;
    }
docs: Extracts all the cached values in a map.
  
  @param map the map to extract the cached values from.
  @return a list of references to cached values in the map. If the is empty, and empty list is
  returned.