The request type for CatalogClient.getEntitiesByRefs.
The list of entity refs to fetch.
The returned list of entities will be in the same order as the refs, and null will be returned in those positions that were not found.
Optional
If given, return only the parts of each entity that match the field declarations.
If given, return only entities that match the given filter.
The request type for CatalogClient.getEntitiesByRefs.