使用代码C#的POST未获得与浏览提交相同的响应

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

class Program
{
    static async Task Main(string[] args)
    {
        using (HttpClient client = new HttpClient())
        {
            // 设置请求头
            client.DefaultRequestHeaders.Add("User-Agent", "Mozilla/5.0");
            
            // 设置请求体
            var content = new FormUrlEncodedContent(new[]
            {
                new KeyValuePair<string, string>("param1", "value1"),
                new KeyValuePair<string, string>("param2", "value2")
            });

            // 发送POST请求
            HttpResponseMessage response = await client.PostAsync("http://example.com/api", content);

            // 获取响应内容
            string responseContent = await response.Content.ReadAsStringAsync();
            
            // 处理响应内容
            Console.WriteLine(responseContent);
        }
    }
}