default byte getFlipByte() {
    return FlipUtil.convertToByte(getFlip());
  }
Flip flag the upstream job whether happened failover or restored from a last completed
checkpoint, flip is true means downstream job should retract the duplicate data in the log
queue. flip is false means this is a normal data in the log queue(e.g. Kafka).

@return true: retract message in the log queue, false: regard the message as normal data.
amoro-format-iceberg/src/main/java/org/apache/amoro/log/LogData.java