Method DistinctByRedb<TKey>(Expression<Func<IRedbObject, TKey>>)

DISTINCT ON (base_field) - one object per unique IRedbObject base field value.
Automatically adds field to beginning of ORDER BY (PostgreSQL requirement).
Uses IRedbObject for compile-time safety - Props not visible!

IRedbQueryable<TProps> DistinctByRedb<TKey>(Expression<Func<IRedbObject, TKey>> keySelector)