post man以Content-type: application/octet-stream方式请求api

在请求头headers中将Content-type改为application/octet-stream方式（流方式），发送数据

后端api 

        //控制器要继承ControllerBase



        [HttpPost]
        [DontWrapResult]
        public async Task GetReturnStateAsync() {
            try
            {
                using (var ms = new MemoryStream(2048))
                {
                    await Request.Body.CopyToAsync(ms);
                    var bs = ms.ToArray();//得到二进制数据
                    string s = Encoding.UTF8.GetString(bs);//MemoryStream转string
                    var data = Newtonsoft.Json.JsonConvert.DeserializeObject(s);//反序列化
                    string aa = data.msgdata.result.ToString();//取值    
                    if (!string.IsNullOrEmpty(aa))
                    {
                        return new { statusCode = "00", desc = "成功" };
                    }
                    else
                    {
                        return new { statusCode = "03", desc = "失败" };
                    } 
                }

            }
            catch (Exception e)
            {
                return Json(new { statusCode = "03", desc = e.Message });
            }
            
        }