curl -iH "Host: delaymaster.local" http://127.0.0.1\?delay\=70s
returns
HTTP/1.1 504 Gateway Time-out
Server: nginx/1.14.1
Date: Mon, 12 Nov 2018 21:03:37 GMT
Content-Type: text/html
Content-Length: 183
Connection: keep-alive
<html>
<head><title>504 Gateway Time-out</title></head>
<body bgcolor="white">
<center><h1>504 Gateway Time-out</h1></center>
<hr><center>nginx/1.14.1</center>
</body>
</html>