如何将带有文件的实体作为表单数据从HttpClient发布到C#？

using System;
using System.IO;
using System.Net.Http;
using System.Net.Http.Headers;

class Program
{
    static void Main()
    {
        string filePath = "path/to/file.txt";
        string apiUrl = "https://api.example.com/upload";

        using (var httpClient = new HttpClient())
        using (var form = new MultipartFormDataContent())
        {
            // 读取文件内容
            byte[] fileBytes = File.ReadAllBytes(filePath);

            // 创建文件内容
            var fileContent = new ByteArrayContent(fileBytes);
            fileContent.Headers.ContentType = MediaTypeHeaderValue.Parse("multipart/form-data");

            // 添加文件到表单数据
            form.Add(fileContent, "file", Path.GetFileName(filePath));

            // 发布请求
            var response = httpClient.PostAsync(apiUrl, form).Result;

            // 处理响应
            if (response.IsSuccessStatusCode)
            {
                Console.WriteLine("文件上传成功！");
            }
            else
            {
                Console.WriteLine("文件上传失败！");
            }
        }
    }
}