有个Tengine问题咨询一下，这是我的配置

location / {

if ($enabled_websocket = "true") {

proxy_http_version 1.1;

proxy_set_header Upgrade $http_upgrade;

proxy_set_header Connection "upgrade";

}

proxy_pass https://$upstream;

}

Tengine启动时报错nginx: [emerg] "proxy_http_version" directive is not allowed here，有什么好的解决办法么？我的需求就是针对某些域名使用websocket协议，目前的server_name是匹配规则是二级域名