@Override
      public void memberOffline(InternalDistributedMember member, PersistentMemberID persistentID) {
        if (logger.isDebugEnabled()) {
          Set<PersistentMemberID> members =
              new HashSet<>(cacheDistributionAdvisor.adviseInitializedPersistentMembers().values());
          members.remove(persistentID);

          Set<String> onlineMembers = new HashSet<>();
          collectionTransformer.transform(members, onlineMembers, persistentMemberIdTransformer);

          logger.info(
              "The following persistent member has gone offline for region {}: {}  Remaining participating members for the region include: {}",
              regionPath, persistentMemberIdTransformer.transform(persistentID), onlineMembers);
        }
      }
A persistent member has gone offline. Log the offline member and log which persistent
members are still online (the current persistent view).
geode-core/src/main/java/org/apache/geode/internal/cache/persistence/PersistenceAdvisorImpl.java