How to use Generic，like HandyJSON?

[zhaoxianxin]

struct DSBaseResponse: Mappable {
init?(map: Map) {
}

var code = 0
private var msg: String?
var data: T?
/// 适配没有套到data层中
var total = 0
var rows: T?

mutating func mapping(map: Map) {
    msg <- map["message"]
    total <- map["total"]
    code <- map["code"]
    rows <- map["rows"]
    data <- map["data"]
}

}

T maybe is Any，[T]， [String, Any]，Int ... I cannot let T must confirm protocol Mappable, such as :

struct DSBaseResponse<T: Mappable>: Mappable {
}

how can I design this struct? like HandyJSON, HandyJSON can use like this.

// test
let res = .... network response string
let result = DSBaseResponse(JSONString: res.string)