@Override
    public Result preAppend(ObserverContext<? extends RegionCoprocessorEnvironment> e,
      Append append) throws IOException {
      updateMutationAddingTags(append);
      return null;
    }
Test that we can do reverse scans when writing tags and using DataBlockEncoding. Fails with an
exception for PREFIX, DIFF, and FAST_DIFF
hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestTags.java