@Override
  protected int getTestCountForTestWritesWhileScanning() {
    return 10;
  }
@return A region on which you must call {@link HBaseTestingUtil#closeRegionAndWAL(HRegion)}
        when done.
hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestHRegionWithInMemoryFlush.java