URLRequestを作成
var urlRequest = URLRequest(url: requestUrl)
urlRequest.httpMethod = "POST"
URLRequestにCookieをセット
urlRequest.setValue("key=value", forHTTPHeaderField: "Cookie")
urlRequest.httpShouldHandleCookies = true
AlamofireでURLRequestを送信
Alamofire.request(urlRequest).responseData { response in
}