private DiskRegionView getDiskRegionById(long drId) {
    DiskRegionView result = drMap.get(drId);
    if (result == null) {
      result = parent.getById(drId);
    }
    return result;
  }
Set of members that have been revoked. We keep track of the revoked members so that we can
indicate to the user a member has been revoked, rather is simply conflicting
geode-core/src/main/java/org/apache/geode/internal/cache/DiskInitFile.java