This looks interesting, although adding language extensions makes me a bit nervous. What's the ABI compatibility story when targeting Cocoa? Can I mix and match with native Swift classes? Is the native Swift runtime used?
The language extensions are there to support concepts that don't exist in Swift, for example await and exception handling are pretty much a requirement when targetting .NET and Java/Android.
It's ABI compatible with Cocoa, all classes end up usable from Cocoa.
