private void rollWalsAndWaitForDeque(int numRs) throws IOException {
    RegionInfo regionInfo =
      UTIL1.getHBaseCluster().getRegions(tableName.getName()).get(0).getRegionInfo();
    for (int i = 0; i < numRs; i++) {
      WAL wal = UTIL1.getHBaseCluster().getRegionServer(i).getWAL(regionInfo);
      wal.rollWriter();
    }
    waitForLogAdvance(numRs);
  }
This test make sure we replicate all the enties from the non empty WALs which are surrounding
the empty WALs
@throws Exception throws exception
hbase-server/src/test/java/org/apache/hadoop/hbase/replication/TestReplicationEmptyWALRecovery.java