.net core api迁移 3.0后Post 405 Method Not Allowed

问题由来：.net core api之前是用 .net core 2.0开发的，测试过都是正常的，近期升级到了3.0，发现api get正常，post提示400，405 Method Not Allowed

查找没有找到原因，就在本地调试，提示错误信息：

System.InvalidOperationException: Synchronous operations are disallowed. Call ReadAsync or set AllowSynchronousIO to true instead.

错误原因：.net core 3.0不允许同步操作，必须改成异步方式

解决方法：将原来的ReadToEnd(),修改为ReadToEndAsync(), 问题得到解决。

            using (StreamReader reader = new StreamReader(Request.Body, Encoding.UTF8))
            {
                result = await reader.ReadToEndAsync(); //升级3.0不允许同步操作，必须异步
                Logger.Info("FactoryBarCode：" + result);
            }

 另一种办法：

It's worth noting that if you host on kestrel directly then your Program.cs should have appropriate ConfigureKestrel call

   public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
            WebHost.CreateDefaultBuilder(args)
                .UseStartup<Startup>()
                .ConfigureKestrel((context, options) =>
                {
                    options.AllowSynchronousIO = true;
                })