private static FieldToRowDataConverter wrapIntoNullableConverter(
            FieldToRowDataConverter converter) {
        return obj -> {
            if (obj == null) {
                return null;
            }
            return converter.convert(obj);
        };
    }
Base class of Field To RowData Converters.
inlong-sort/sort-formats/format-rowdata/format-rowdata-base/src/main/java/org/apache/inlong/sort/formats/base/FieldToRowDataConverters.java