The bigger news here is that for the first time in 20+ years, all platforms are using the same codebase and that includes iOS, Android, Mac and Windows.
Looks interesting PoC. I have written multiple extensions for PostgreSQL in Go. The hardest part is not "glueing" together the tools to make it work. Most of the time it's much more easier and faster to just write in C (C++ with wrapper).
There are many cases you should consider, like returning rows (composite types) and implementing trigger functions.
I worked at BAO 6 years ago, it was my first job as a software engineer. I was working on 1m Schmidt telescope and even though we had many problems (due to insufficient funding) we were excited and motivated. Nowadays, BAO is mainly about "art stuff". I'm not against using outdated equipments for artistic use, but it's a research center/observatory and not a museum.