从python HTTP请求转换为C# HTTP请求

import requests

url = "http://example.com/api"
data = {"key": "value"}
headers = {"Content-Type": "application/json"}

response = requests.post(url, json=data, headers=headers)
print(response.text)

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

class Program
{
    static async Task Main(string[] args)
    {
        string url = "http://example.com/api";
        string data = "{\"key\": \"value\"}";
        string contentType = "application/json";

        using (HttpClient client = new HttpClient())
        {
            StringContent content = new StringContent(data, Encoding.UTF8, contentType);
            HttpResponseMessage response = await client.PostAsync(url, content);
            string result = await response.Content.ReadAsStringAsync();
            Console.WriteLine(result);
        }
    }
}