The article https://developer.xamarin.com/guides/cross-platform/macios/binding/ mentions how Xamarin can use its own library written using Objective-C. Is there any documentation for doing the same with my own map written in Swift? https://developer.xamarin.com/guides/ios/advanced_topics/embedded_frameworks/ talks about using built-in frameworks, but doesn't say anything about fast. Does the same work?
Binding Swift libraries are not officially supported, but you can find documentation on how to do this:
https://medium.com/@Flash3001/binding-swift-libraries-xamarin-ios-ff32adbc7c76