@Override
  public InternalScanner preFlush(ObserverContext<? extends RegionCoprocessorEnvironment> c,
    Store store, InternalScanner scanner, FlushLifeCycleTracker tracker) throws IOException {
    return new DelegatingInternalScanner(scanner);
  }
RegionObserver that just reimplements the default behavior, in order to validate that all the
necessary APIs for this are public This observer is also used in
{@link TestFromClientSideWithCoprocessor} and {@link TestCompactionWithCoprocessor} to make sure
that a wide range of functionality still behaves as expected.
hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/NoOpScanPolicyObserver.java