Hi! I just wanted to let you know that this looks good on the surface. I'll likely pull it in when I have some extra time to test it out a bit more myself as well.

Thanks!

Whoops, one more thing: Can you give an example of its usage? It looks like the test is an example, but I wanted to confirm that.

I'll use that to update the readme.md docs.

Great, thanks for the update.

RE: usage you would typically start with Request::HEADER_X_FORWARDED_ALL and use a bitwise xor to exclude the headers you do not want, i.e.

// all x-forwarded-* headers except for x-forwarded-port
Request::HEADER_X_FORWARDED_ALL ^ Request::HEADER_X_FORWARDED_PORT
// all x-forwarded-* headers except for x-forwarded-host
Request::HEADER_X_FORWARDED_ALL ^ Request::HEADER_X_FORWARDED_HOST

Here's an example from Symfony.