新版本RestRequest不存在ConfigureWebRequest定义该调用什么替代方法

使用新版本RestRequest开发时，会抛出如下编译错误：restRequest does not contain a definition for ConfigureWebRequest

原有代码中通过ConfigureWebRequest配置Web请求参数的逻辑无法在新版本中运行，需要找到替代实现。
原报错代码如下：

public async Task Login()
{
    try
    {
        ServicePointManager.ServerCertificateValidationCallback += delegate {
            return true;
        };
        var url = "https://192.0.0.0:50000/b1s/v1/Login";
        var client = new RestClient(url);
        var request = new RestRequest(url, Method.Post);

        // 该行在新版本RestSharp中会触发编译错误
        request.ConfigureWebRequest(r => { r.ProtocolVersion = HttpVersion.Version10; });

        request.AddHeader("Content-Type", "application/json");
        request.AddHeader("B1S-WCFCompatible", "true");
        request.AddHeader("B1S-MetadataWithoutSession", "true");
        request.AddHeader("Accept-Encoding", "gzip, deflate, br");
        var body = new
        {
            CompanyDB = "Prueba",
            Password = "****",
            UserName = "Hackerman"
        };
        var x = JsonConvert.SerializeObject(body);
        request.AddParameter("application/json", x, ParameterType.RequestBody);             
        RestResponse response = await client.ExecuteAsync(request);
        var output = response.Content;
        MessageBox.Show(output + response.ErrorException.Message + response.ErrorMessage);
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.StackTrace);
    }
}

ConfigureWebRequest是RestSharp v106及更早版本的API，该版本底层依赖HttpWebRequest实现。v107及之后的新版本完全重构了底层逻辑，切换为HttpClient实现，该方法已被正式移除，对应配置能力可通过以下两种方式实现：

• 单请求配置：和原代码作用范围一致，仅对当前请求生效，使用OnBeforeRequest委托配置底层请求消息即可，替换原报错行的代码如下：

request.OnBeforeRequest = httpRequestMsg =>
{
    httpRequestMsg.Version = HttpVersion.Version10;
    return ValueTask.CompletedTask;
};

• 全局配置：如果项目中所有请求都需要统一配置参数，可以在初始化RestClient时通过RestClientOptions统一设置，无需每个请求单独编写配置逻辑：

var clientOptions = new RestClientOptions(url)
{
    ConfigureMessageHandler = handler =>
    {
        // 可以在这里替换原全局ServicePointManager的证书校验逻辑，避免全局配置副作用
        if (handler is HttpClientHandler httpClientHandler)
        {
            httpClientHandler.ServerCertificateCustomValidationCallback = (_, _, _, _) => true;
        }
        return handler;
    }
};
var client = new RestClient(clientOptions);

注意：新版本RestSharp不再依赖HttpWebRequest，因此原代码中全局注册ServicePointManager.ServerCertificateValidationCallback的写法不推荐继续使用，优先通过RestClientOptions做客户端级别的证书、代理等配置，避免全局配置影响应用内其他HTTP请求。

修改后可正常运行的完整代码：

public async Task Login()
{
    try
    {
        var url = "https://192.0.0.0:50000/b1s/v1/Login";
        var client = new RestClient(url);
        var request = new RestRequest(url, Method.Post);

        // 替换原ConfigureWebRequest配置逻辑
        request.OnBeforeRequest = msg =>
        {
            msg.Version = HttpVersion.Version10;
            return ValueTask.CompletedTask;
        };

        request.AddHeader("Content-Type", "application/json");
        request.AddHeader("B1S-WCFCompatible", "true");
        request.AddHeader("B1S-MetadataWithoutSession", "true");
        request.AddHeader("Accept-Encoding", "gzip, deflate, br");
        var body = new
        {
            CompanyDB = "Prueba",
            Password = "****",
            UserName = "Hackerman"
        };
        var x = JsonConvert.SerializeObject(body);
        request.AddParameter("application/json", x, ParameterType.RequestBody);             
        RestResponse response = await client.ExecuteAsync(request);
        var output = response.Content;
        MessageBox.Show(output + response.ErrorException?.Message + response.ErrorMessage);
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.StackTrace);
    }
}

内容的提问来源于stack exchange，提问作者Hackerman