nginx discards the "HTTP/1.1 304 Not Modified\r\n"
.
nginx uses (and eats) the Status
header.
If my fastcgi program returns the header "Status: 304\r\n"
.
Then I get this response:
HTTP/1.1 304
Server: nginx/1.6.2
Date: Sat, 21 May 2016 10:49:27 GMT
Connection: keep-alive
As you can see there is no Status: 304
header. It has been eaten by nginx.