iOSのネイティブでユーザ名とパスワードを入力し、認証を行った後、そのセッションを維持したままWebViewへ飛ばす方法

Alamofire.request("<url>",parameters: params)
    .responseString { response in
    let cookies = HTTPCookie.cookies(withResponseHeaderFields: response.response?.allHeaderFields as! [String : String], for: (response.response?.url!)!)

    for i in 0 ..< cookies.count {
        let cookie = cookies[i]
        HTTPCookieStorage.shared.setCookie(cookie)
    }   

}

let authUrl = URL(string: "認証URL")
let url = URL(string: "ロードしたいURL")

var request = URLRequest(url: url)
let cookies = HTTPCookieStorage.shared.cookies(for: authUrl! as URL)
let header = HTTPCookie.requestHeaderFields(with: cookies!)
// Cookieをセットする
request.allHTTPHeaderFields = header
// webViewをロードする
webView.loadRequest(request as URLRequest)