@Override
    public String toString() {
      StringBuilder sb = new StringBuilder();
      return sb.append("StoreFileReference[region=").append(regionName).append(", files=")
        .append(familyToFiles).append("]").toString();
    }
A reference to a collection of files in the archive directory for a single region.
hbase-server/src/main/java/org/apache/hadoop/hbase/quotas/FileArchiverNotifierImpl.java