C#console app中的HTTP Post不会返回与浏览器请求相同的内容

using System;
using System.Net;
using System.IO;
using System.Text;

class Program
{
    static void Main()
    {
        string url = "https://example.com/post";
        string data = "key1=value1&key2=value2";
        string contentType = "application/x-www-form-urlencoded";
        string userAgent = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.3";

        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
        request.Method = "POST";
        request.ContentType = contentType;
        request.UserAgent = userAgent;
        request.CookieContainer = new CookieContainer();

        byte[] byteData = Encoding.UTF8.GetBytes(data);
        request.ContentLength = byteData.Length;

        using (Stream postStream = request.GetRequestStream())
        {
            postStream.Write(byteData, 0, byteData.Length);
        }

        using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
        {
            using (StreamReader reader = new StreamReader(response.GetResponseStream()))
            {
                string responseData = reader.ReadToEnd();
                Console.WriteLine(responseData);
            }
        }
    }
}