default String format(MetaField metaField) {
        if (metaField == MetaField.PROCESS_TIME) {
            return "AS PROCTIME()";
        }
        return String.format("%s METADATA FROM '%s'%s",
                getMetadataType(metaField), getMetadataKey(metaField), isVirtual(metaField) ? " VIRTUAL" : "");
    }
Format string by Flink SQL

@param metaField The meta field
@return The string that format by Flink SQL
inlong-sort/sort-common/src/main/java/org/apache/inlong/sort/protocol/Metadata.java