这两个异步函数的区别

你好,我不明白下面两个asnyc函数的区别,有人能给我解释一下吗?它们都不返回IRestResponse,因此我无法访问StatusCode字段。我必须在这里铸造吗?

public async Task<IRestResponse> Post<T>(string Ressource, T ObjTOPost) where T : new()
{
    return await Task.Factory.StartNew(() =>
    {
        var client = new RestClient("test.com");
        var request = new RestRequest(Ressource, Method.POST);

        var response = client.Execute(request);

        return response;
    });
}

还有这个:

public async Task<IRestResponse> Post<T>(string Ressource, T ObjTOPost) where T : new()
{
    var client = new RestClient("test.com");

    var request = new RestRequest(Ressource, Method.POST);

    var response = await client.ExecuteTaskAsync<T>(request);

    return response;
}