[Enhancement] Trigger on custom HTTP header

[martin-juul]

Hi!

Would it be possible to have the extension trigger on a custom header? Header key and value should be up to the user imo.

Proposed options

[PhilipReasa]

I love this idea. Unfortunately I don't develop in PHP any more, so I probably wont be adding this feature. I would LOVE a PR for it though.

The only tricky part that I anticipate is listening for the http headers. That is currently not happening anywhere, but absolutely can be done.

Thanks for the great idea. Let me know if you need any help making a PR.