将curl --form转换为C#

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

class Program
{
    static async Task Main(string[] args)
    {
        using var httpClient = new HttpClient();
        
        var formData = new MultipartFormDataContent();
        formData.Add(new StringContent("value1"), "field1");
        formData.Add(new StringContent("value2"), "field2");
        formData.Add(new ByteArrayContent(System.IO.File.ReadAllBytes("file.txt")), "file", "file.txt");

        var response = await httpClient.PostAsync("http://example.com/upload", formData);
        var responseContent = await response.Content.ReadAsStringAsync();

        Console.WriteLine(responseContent);
    }
}