private boolean shouldScheduleConsumer() {
    int currentEpochAndState = epochAndState;
    if (writerBroken(currentEpochAndState) || waitingRoll(currentEpochAndState)) {
      return false;
    }
    return consumerScheduled.compareAndSet(false, true);
  }
For {@link FSHog},here may catch IOException,but for {@link AsyncFSWAL}, the code doesn't
go in here.
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/wal/AbstractFSWAL.java