@Override
  public java.util.Set getRootRegionNames() {
    Set set = info.getRootRegionNames();
    if (set == null) {
      set = Collections.EMPTY_SET;
    }
    return set;
  }
Value that uniquely identifies an instance of a cache for a given member.
geode-core/src/main/java/org/apache/geode/admin/internal/SystemMemberCacheImpl.java