Use of delegate in Swift

Today, I wrote a delegate and encountered the following questions:

The protocol here is problematic, if your protocol represents an object that implements the MO function, which is written id<protocol> in OC, and in Swift it should be written like this:

 
protocol MyPickerViewDelegate: NSObjectProtocol {

    func pickerConfirm(content:String)
}

This is also because structs and enums can implement protocols in addition to class, but they are both value types, not reference types!

Use of delegate in Swift