如何使用C#创建上述请求结构以调用服务

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

public async Task<string> CallServiceAsync()
{
    using (HttpClient client = new HttpClient())
    {
        // 设置请求的URL
        string url = "服务的URL地址";

        // 创建请求结构
        HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Post, url);

        // 设置请求头部信息
        request.Headers.Add("HeaderName", "HeaderValue");

        // 设置请求内容
        string requestBody = "请求的内容";
        request.Content = new StringContent(requestBody, System.Text.Encoding.UTF8, "application/json");

        // 发送请求并获取响应
        HttpResponseMessage response = await client.SendAsync(request);

        // 处理响应
        if (response.IsSuccessStatusCode)
        {
            string responseBody = await response.Content.ReadAsStringAsync();
            return responseBody;
        }
        else
        {
            throw new Exception("请求失败：" + response.StatusCode);
        }
    }
}

string response = await CallServiceAsync();
Console.WriteLine(response);