swift 4.0 ，Alamofire请求框架添加超时时间

先上代码，再作解释

/// 网络请求框架 GET POST/// - Parameters:
    ///   - url: url
    ///   - method: GET POST
    ///   - parameters: 参数
    ///   - completion: 完成回调
    func request(url: URLConvertible,
                 method: HTTPMethod = .get ,
                 timeoutInterval: TimeInterval = 10,
                 headers: HTTPHeaders? = nil,
                 parameters: Parameters? = nil,
                 completion: @escaping (_ value: Any?,_ isSuccess: Bool)->()) {
        //
        guard var myURLRequest = try? URLRequest(url: url, method: method, headers: headers) else{
            print("错误的URLRequest")
            return
        }
        guard let encodedURLRequest = try? URLEncoding.default.encode(myURLRequest, with: parameters) else{
            print("错误的URLEncoding")
            return
        }
        //
        myURLRequest.timeoutInterval = timeoutInterval
        //auth
        SessionManager.default.delegate.sessionDidReceiveChallenge = {
            session,challenge in
            return (URLSession.AuthChallengeDisposition.useCredential,URLCredential(trust:challenge.protectionSpace.serverTrust!))
        }
        //
        Alamofire.request(encodedURLRequest).responseJSON { (response) in
            //
            if response.result.isSuccess {
                completion(response.result.value,true)
            }else {
                print("错误的：")
                print(url)
                print(response.error!)
                completion(nil,false)
            }
        }


    }

Alamofire虽然可以设置总超时时间，但是那种必须要设置sessionManager，而且不能为单一请求，单独设置请求时间。所以来设置URLRequest，通过设置timeoutInterval属性来为每个请求设置超时时间。