private static RegionInfo buildRegionInfo(TableName tn, byte[] start, byte[] end) {
    return RegionInfoBuilder.newBuilder(tn).setStartKey(start).setEndKey(end).build();
  }
@return Attempts to calculate a new {@link RegionInfo} that covers the region range described
        in {@code hole}.
hbase-server/src/main/java/org/apache/hadoop/hbase/master/janitor/MetaFixer.java