如何使用ApiClient.Default.CallApi()？

using System;
using System.Net.Http;
using System.Threading.Tasks;

public class ApiClient
{
    public static HttpClient Default { get; } = new HttpClient();

    public static async Task<string> CallApi(string url)
    {
        HttpResponseMessage response = await Default.GetAsync(url);
        response.EnsureSuccessStatusCode();
        return await response.Content.ReadAsStringAsync();
    }
}

public class Program
{
    public static async Task Main()
    {
        string apiUrl = "https://api.example.com/data";
        string result = await ApiClient.CallApi(apiUrl);
        Console.WriteLine(result);
    }
}

using System;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;
using Newtonsoft.Json;

public class ApiClient
{
    public static HttpClient Default { get; } = new HttpClient();

    public static async Task<string> CallApi(string url, object data)
    {
        string json = JsonConvert.SerializeObject(data);
        StringContent content = new StringContent(json, Encoding.UTF8, "application/json");
        HttpResponseMessage response = await Default.PostAsync(url, content);
        response.EnsureSuccessStatusCode();
        return await response.Content.ReadAsStringAsync();
    }
}

public class DataModel
{
    public string Name { get; set; }
    public int Age { get; set; }
}

public class Program
{
    public static async Task Main()
    {
        string apiUrl = "https://api.example.com/data";
        DataModel model = new DataModel { Name = "John", Age = 30 };
        string result = await ApiClient.CallApi(apiUrl, model);
        Console.WriteLine(result);
    }
}