static void putData(HRegion region, Durability durability, int startRow, int numRows, byte[] qf,
    byte[]... families) throws IOException {
    for (int i = startRow; i < startRow + numRows; i++) {
      Put put = new Put(Bytes.toBytes("" + i));
      put.setDurability(durability);
      for (byte[] family : families) {
        put.addColumn(family, qf, null);
      }
      region.put(put);
      LOG.info(put.toString());
    }
  }
For this test,the spied {@link AsyncFSWAL} can not work properly because of a Mockito defect
that can not deal with classes which have a field of an inner class. See discussions in
HBASE-15536.When we reuse the code of {@link AsyncFSWAL} for {@link FSHLog}, this test could
not work for {@link FSHLog} also.
hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestHRegion.java