Add a custom "X-forwarded-for" header

This is the code I ended up going with! Thanks to the community for all the help like always!

when HTTP_REQUEST {
    HTTP::header remove "X-Forwarded-For"
    HTTP::header replace "X-Forwarded-For" [IP::client_addr]
     HTTP::header replace "X-Forwarded-For" 10.102.22.53
}