Removing response headers

[Jeff Kaufman]

In a header filter, to remove a filter that's already been set, I see
two options:

1. set the header's hash to 0
2. actually delete the header from r->headers_out

The second is much more complex and requires allocating memory (see
ngx_http_headers_more_rm_header_helper in
https://github.com/agentzh/headers-more-nginx-module/blob/master/src/ngx_http_headers_more_util.c#L294)
so I'd rather use the first, but is there a reason to prefer the
second?

Jeff Kaufman
ngx_pagespeed