@Override
    public StripeMultiFileWriter createWriter() throws IOException {
      return new StripeMultiFileWriter.BoundaryMultiWriter(comparator, targetBoundaries, null,
        null);
    }
@param targetBoundaries New files should be written with these boundaries.
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/StripeStoreFlusher.java