@Override
    public void sync(boolean forceSync) throws IOException {
      Threads.sleep(ThreadLocalRandom.current().nextInt(10));
      super.sync(forceSync);
      Threads.sleep(ThreadLocalRandom.current().nextInt(10));
    }
ProtobufLogWriter that simulates higher latencies in sync() call
hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/wal/TestLogRollingNoCluster.java