That's pretty much how every one emulates them, with a `map[{TYPE}]struct{}` or possibly `map[{TYPE}]bool` if the space isn't a problem, and you find it easier

That's pretty much how every one emulates them, with a `map[{TYPE}]struct{}` or possibly `map[{TYPE}]bool` if the space isn't a problem, and you find it easier to read (or if you want to be able to check for membership by indexing instead of using the comma ok idiom).