webman nginx代理 怎么支持 Transfer-Encoding: chunked？

server {
  server_name 站点域名;
  listen 80;
  access_log off;
  proxy_buffering off;
  root /your/webman/public;

  location ^~ / {
      proxy_set_header X-Real-IP $remote_addr;
      proxy_set_header Host $host;
      proxy_set_header X-Forwarded-Proto $scheme;
      proxy_http_version 1.1;
      proxy_set_header Connection "";
      if (!-f $request_filename){
          proxy_pass http://127.0.0.1:8787;
      }
  }
}