private static Map<InternalDistributedMember, PersistentMemberID> getSubMapForLiveMembers(
      Set<InternalDistributedMember> membersToPersistOfflineEqual,
      Map<InternalDistributedMember, PersistentMemberID> bucketMap) {
    if (bucketMap == null) {
      return null;
    }
    Map<InternalDistributedMember, PersistentMemberID> persistMap = new HashMap<>();
    for (InternalDistributedMember member : membersToPersistOfflineEqual) {
      if (bucketMap.containsKey(member)) {
        persistMap.put(member, bucketMap.get(member));
      }
    }
    return persistMap;
  }
Close the distributed system, cache servers, and gateways. Clears the rootRegions and
partitionedRegions map. Marks the cache as closed.

@see SystemFailure#emergencyClose()
geode-core/src/main/java/org/apache/geode/internal/cache/GemFireCacheImpl.java