@Override
  public void beforeShipped() throws IOException {
    Collection<StoreFileWriter> writers = writers();
    if (writers != null) {
      for (StoreFileWriter writer : writers) {
        if (writer != null) {
          writer.beforeShipped();
        }
      }
    }
  }
Subclasses override this method to be called before we close the give writer. Usually you can
append extra metadata to the writer.
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/AbstractMultiFileWriter.java