@Override
  public String toString() {
    return MoreObjects.toStringHelper(this)
        .add("changeSnapshotId", changeSnapshotId)
        .add("snapshotTimestamp", snapshotTimestampMs)
        .toString();
  }
use Long.MIN_VALUE to indicate the earliest offset
amoro-format-mixed/amoro-mixed-flink/amoro-mixed-flink-common/src/main/java/org/apache/amoro/flink/read/hybrid/enumerator/MixedFormatEnumeratorOffset.java