问无法找到类型或命名空间名称"IRestResponse“(您是缺少使用指令还是程序集引用？)

EN

public async Task<CezanneToken> GetAccessToken()
{
    var client = new RestClient(WebConfigurationManager.AppSettings["TokenUrl"]);
    var request = new RestRequest();
    request.Method = Method.Post;
    request.AddHeader("cache-control", "no-cache");
    request.AddHeader("content-type", "application/x-www-form-urlencoded");
    request.AddParameter("application/x-www-form-urlencoded", "grant_type=client_credentials&client_id=" + WebConfigurationManager.AppSettings["ClientId"] + "&client_secret=" + WebConfigurationManager.AppSettings["ClientSecret"] + "", ParameterType.RequestBody);

    IRestResponse response = await client.ExecuteAsync(request);
    string serStatus = ((RestResponseBase)response).Content;
    CezanneToken details = JsonConvert.DeserializeObject<CezanneToken>(serStatus);
    string Token = details.access_token;
    
    return details;
}