public Long getRetractingEpicNo() {
    return retractingEpicNo;
  }
Key: upstream job id + "_" + epicNo, Value: epic start offset
amoro-format-mixed/amoro-mixed-flink/amoro-mixed-flink-common/src/main/java/org/apache/amoro/flink/read/source/log/kafka/LogKafkaPartitionSplitState.java