// *** in version 6.1: ***
//the whole extension can leave the actor

@MainActor
final class Screen {
    let title = "Main"

    func show() {
        print("showing \(title)")
    }
}

nonisolated extension Screen {
    func describe() -> String {
        "Screen"
    }
}

let screen = Screen()
screen.show()
//showing Main

print(screen.describe())
//printed Screen