> found my suspicion confirmed. cast[PResult](s.x) had Nim copy the content (32 > bytes) rather than simply
Great. It would be nice if you could push minimal example code for that behaviour to Nim issue tracker, it may be a bug. I personally avoid casts myself, but I would not assume it generation a copy. Note also that you may have to use -d:danger and -d:release at the same time for maximum speed. -d:danger should include -d:release, but recently it did not, there was a forum post and soon a fix.
