protected Set<String> orphanFileCleanNeedToExcludeFiles() {
    return Sets.union(
        IcebergTableUtil.getAllContentFilePath(table),
        IcebergTableUtil.getAllStatisticsFilePath(table));
  }
Purge data older than the specified UTC timestamp

@param expirationConfig expiration configs
@param instant timestamp/timestampz/long field type uses UTC, others will use the local time
    zone
amoro-ams/src/main/java/org/apache/amoro/server/optimizing/maintainer/IcebergTableMaintainer.java