如何使用HTTPRequestMessage添加SOAP身份验证头？

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

class Program
{
    static async Task Main(string[] args)
    {
        // 创建一个HTTPRequestMessage对象
        var request = new HttpRequestMessage(HttpMethod.Post, "https://example.com/soap-endpoint");

        // 创建身份验证头
        var authHeader = new AuthenticationHeaderValue("Basic", Convert.ToBase64String(System.Text.Encoding.ASCII.GetBytes("username:password")));

        // 将身份验证头添加到HTTPRequestMessage对象中
        request.Headers.Authorization = authHeader;

        // 发送HTTP请求
        using (var client = new HttpClient())
        {
            var response = await client.SendAsync(request);
            // 处理响应
        }
    }
}