Send region name to header from Cloudflare Worker, then fetch with PHP

I’m proxying my website traffic through Cloudflare and would like to take advantage of the geolocation functionality shown here: https://developers.cloudflare.com/workers/examples/geolocation-hello-world/.

The website is on WordPress and I want to be able to fetch the geolocation using PHP in a plugin. I saw on here that by default you can call the country by using:

$userCountry = $_SERVER["HTTP_CF_IPCOUNTRY"];

But I haven’t found anything that will do the same for the region code. Therefore I’m trying to set up a Cloudflare worker which can pass the result of request.cf.region to the header, so that I can call it like so:

$regionCode = $_SERVER["HTTP_CF_IPREGIONCODE"];

Am I on the right track here? Could someone please give me a pointer on how to achieve what I describe?

Solution found here: Geolocate requests with Cloudflare workers