public static Schema appendChangeStoreMetadataColumns(Schema sourceSchema) {
    List<NestedField> columns = new ArrayList<>(sourceSchema.columns());
    columns.add(MetadataColumns.TRANSACTION_ID_FILED);
    columns.add(MetadataColumns.FILE_OFFSET_FILED);
    columns.add(MetadataColumns.CHANGE_ACTION_FIELD);
    return new Schema(columns);
  }
Addition metadata columns for {@link MixedTable}
amoro-format-iceberg/src/main/java/org/apache/amoro/table/MetadataColumns.java