public static void populateWithOriginalValues(Record rec, Record original) {
    int dataOffset = SERDE_META_COLS.size();
    for (int i = dataOffset; i < dataOffset + original.size(); ++i) {
      original.set(i - dataOffset, rec.get(i));
    }
  }
Get the original record from the updated record. Populate the `original` with the filed values from `rec`.
@param rec The record read by the file scan task, which contains both the metadata fields and the row data fields
@param original The record object to populate. The end result is the original record before the update.
iceberg/iceberg-handler/src/main/java/org/apache/iceberg/mr/hive/IcebergAcidUtil.java