Wrong type definition for Duration due to converter

When writing a duration type parameter to the database, Spring defines it as a String after using converters, it can be seen that JRS310Converters.DurationToStringConverter is being used, but I need its real type and not a modified one.

Now I have to write a strange converter that is used when writing to the database. I need exactly its type. further it is used for custom codec
@WritingConverter
class DurationToDurationConverter : Converter<Duration, Duration> {
override fun convert(source: Duration): Duration = source
}

Start by examining JRS310Converters.DurationToStringConverter and the converter registration involved in writing Duration values. Reproduce the reported type mapping with a custom codec, then determine the expected type and add regression coverage for the database-writing path. Done means Duration is exposed to the codec with its real type rather than the converted String type.