Description
It would be nice of one could get invalid cache items of a tag-based cache adapter to be able to warmup a cache after some items got invalid.

Example
Database query and its result get saved as serialized object together with tag 'test'. Due to a change all cache items with tag 'test' get invalid (via TagAwareAdapter::invalidateTags(['test'])). Later on it would be nice to fetch all invalid entries to re-warmup the cache by executing the queries and fill the cache with the current values.