ASP.NET Core 因为 Nginx 配置 Connection 为 Upgrade 导致 Kestrel 返回 400 错误

GET /foo HTTP/1.1
Host: www.example.com
Connection: upgrade
Upgrade: example/1, foo/2

    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade"; 

            var httpClient = new HttpClient();

            httpClient.DefaultRequestHeaders.Clear();
            httpClient.DefaultRequestHeaders.Add("Upgrade", "");
            httpClient.DefaultRequestHeaders.Add("Connection", "Upgrade");

            app.UseExceptionHandler(builder =>
            {
                // 这是会进来的
            });

dbug: Microsoft.AspNetCore.Server.Kestrel[39]
      Connection id "0HM5U310J8F34" accepted.
dbug: Microsoft.AspNetCore.Server.Kestrel[1]
      Connection id "0HM5U310J8F34" started.
dbug: Microsoft.AspNetCore.Server.Kestrel[17]
      Connection id "0HM5U310J8F34" bad request data: "Requests with 'Connection: Upgrade' cannot have content in the request body."
Microsoft.AspNetCore.Server.Kestrel.Core.BadHttpRequestException: Requests with 'Connection: Upgrade' cannot have content in the request body.
   at Microsoft.AspNetCore.Server.Kestrel.Core.BadHttpRequestException.Throw(RequestRejectionReason reason)
   at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.Http1MessageBody.For(HttpVersion httpVersion, HttpRequestHeaders headers, Http1Connection context)
   at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.Http1Connection.CreateMessageBody()
   at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.HttpProtocol.ProcessRequests[TContext](IHttpApplication`1 application)
   at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.HttpProtocol.ProcessRequestsAsync[TContext](IHttpApplication`1 application)

server {
    listen        80;
    server_name   example.com *.example.com;
    location / {
        proxy_pass         http://localhost:5000;
        proxy_http_version 1.1;
        proxy_set_header   Upgrade $http_upgrade;
        proxy_set_header   Connection keep-alive;
        proxy_set_header   Host $host;
        proxy_cache_bypass $http_upgrade;
        proxy_set_header   X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header   X-Forwarded-Proto $scheme;
    }
}

http {
  map $http_connection $connection_upgrade {
    "~*Upgrade" $http_connection;
    default keep-alive;
}

  server {
    listen 80;
    server_name example.com *.example.com;

    # Configure the SignalR Endpoint
    location /hubroute {
      # App server url
      proxy_pass http://localhost:5000;

      # Configuration for WebSockets
      proxy_set_header Upgrade $http_upgrade;
      proxy_set_header Connection $connection_upgrade;
      proxy_cache off;

      # Configuration for ServerSentEvents
      proxy_buffering off;

      # Configuration for LongPolling or if your KeepAliveInterval is longer than 60 seconds
      proxy_read_timeout 100s;

      proxy_set_header Host $host;
      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
      proxy_set_header X-Forwarded-Proto $scheme;
    }
  }
}

  map $http_connection $connection_upgrade {
    "~*Upgrade" $http_connection;
    default keep-alive;
}