Currently the localSetTime field is part of the persisted state in RWConcernDefault. While it makes sense to persist epoch and setTime, localSetTime will vary across the cluster. It should instead be in DistCache::Value (alongside the _isValid atomic bool) as a const Date_t. This would also allow the code that sets localSetTime in ReadWriteConcernDefaults::Cache::lookup() to instead happen when the DistCache::Value objects are constructed (i.e. make the constructor require the localSetTime date).