c# netcore 发送http请求并接收返回数据

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;

namespace c_http2.Controllers
{
    [Route("api/[controller]/[action]")]
    [ApiController]
    public class TestController : ControllerBase
    {
        [HttpPost]
        public IActionResult GetResult()
        {
            Request.ContentType = "application/json";
            var str = new StreamReader(Request.Body);
            var data_text = str.ReadToEnd();
            JObject data = JsonConvert.DeserializeObject<JObject>(data_text);
            string key1 = HttpContext.Request.Headers["key1"];
            string key2 = HttpContext.Request.Headers["key2"];
            data.Add("key1", (JToken)key1);
            data.Add("key2", (JToken)key2);
            return Ok(data);
        }
        [HttpGet]
        public IActionResult ReturnResult()
        {
            var url = "http://localhost:98/api/Test/GetResult";
            string str_postdata = JsonConvert.SerializeObject(new { a = "a123", b = "b234", t = "1212c567" });
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
            request.Method = "POST";
            request.ContentType = "application/json;charset=utf-8";
            //request.ContentLength = Encoding.UTF8.GetByteCount(str_postdata);
            request.Headers.Add("key1", "key1");
            request.Headers.Add("key2", "key2");
            Stream myRequestStream = request.GetRequestStream();
            StreamWriter myStreamWriter = new StreamWriter(myRequestStream, Encoding.GetEncoding("utf-8"));
            myStreamWriter.Write(str_postdata);
            myStreamWriter.Close();

            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            Stream myResponseStream = response.GetResponseStream();
            StreamReader myStreamReader = new StreamReader(myResponseStream, Encoding.GetEncoding("utf-8"));
            string retString = myStreamReader.ReadToEnd();
            JObject bupo = JsonConvert.DeserializeObject<JObject>(retString);
            myStreamReader.Close();
            myResponseStream.Close();
            return Ok(bupo);
        }
    }
}

发送请求，并接收数据，加ContentLength ，接收的时候，字符好像少了两个，导致报错，就直接屏蔽了。