How to implement custom range

[cutsea110]

I would like to implement a range for time(NaiveTime) in postgres.

In postgres, it looks like this (ref. https://www.postgresql.org/docs/13/rangetypes.html)

CREATE FUNCTION time_subtype_diff(x time, y time) RETURNS float8 AS
'SELECT EXTRACT(EPOCH FROM (x - y))' LANGUAGE sql STRICT IMMUTABLE;

CREATE TYPE timerange AS RANGE (
    subtype = time,
    subtype_diff = time_subtype_diff
);

SELECT '[11:10, 23:00]'::timerange;

I'd like to use PgRange<NaiveTime>, but rustc tells me to implement Type<Postgres>.
It looks like the Type implementation needs to implement fn type_info() -> PgTypeInfo, but since PgTypeInfo is pub(crate), it seems to be invisible outside of crate, and I don't think we can construct it.

Could you teach me how to do this?

Thanks.