@Override
  public void close() {
    RegionMap rm = getRecoveredEntryMap();
    if (rm != null) {
      rm.close(null);
    }
  }
This constructor is used when we are closing an existing region. We want to remember that it is
still present in the disk store.
geode-core/src/main/java/org/apache/geode/internal/cache/PlaceHolderDiskRegion.java