@Override
  public Set<PersistentMemberID> getOfflineAndEqualMembers() {
    DiskInitFile dif = ds.getDiskInitFile();
    if (dif == null) {
      return equalMembers.getSnapshot();
    }
    synchronized (dif) {
      return equalMembers.getSnapshot();
    }
  }
Used to initialize a PlaceHolderDiskRegion for a region that is being closed

@param drv the region that is being closed
geode-core/src/main/java/org/apache/geode/internal/cache/AbstractDiskRegion.java