How does vapor proxy a URL

[vine]

We know that nginx can reverse proxy. How can this be achieved in Vapor?

location /testapi/ {
  proxy_redirect off;
  proxy_set_header X-Forward-For $proxy_add_x_forwarded_for;
  proxy_set_header X-Real-IP $remote_addr;
  proxy_set_header Referer 'no-referrer-when-downgrade';
  proxy_pass https://www.google.com/;
}

vapor serve can proxy /testapi to https://www.google.com