Possible Solution for Swift Enum conforming to a protocol

EnumProtocol Solution

enum testEnum: ExampleProtocol{
    case a, b, c
    var simpleDescription: String{
    get{
        return "an example enum"
    }
    set {
        simpleDescription = newValue
    }
    }
    mutating func adjust() {
        simpleDescription += " (whatever)"
    }
}

var protoEnum = testEnum.a
let test = protoEnum.simpleDescription

Here's how I solved it based on kasei's code:

enum ServerResponse: ExampleProtocol {
    case Result(String, String)
    case Error(String)
    var simpleDescription: String {
        get {
            switch self {
            case let .Result(sunrise, sunset):
                return "Sunrise is at \(sunrise) and sunset is at \(sunset)."
            case let .Error(error):
                return "Failure...  \(error)"
            }
        }
    }
    mutating func adjust() {
        switch self {
            case Result(let v1, let v2):
                self = Result(v1 + " (adjusted)", v2 + " (adjusted)")
            case Error(let v1):
                self = Error(v1 + " (adjusted)")
        }
    }
}

var success = ServerResponse.Result("6:00 am", "8:09 pm")
var failure = ServerResponse.Error("Out of cheese.")
success.adjust()
failure.adjust()
print(success.simpleDescription)
print(failure.simpleDescription)