Is there a way for header routing to test for withoutHeader

[sourceful-karlson]

Please describe your use case / problem. I would like to have a mapping where the header routing would test for without header

something like in istio withoutHeader: preview: "*"

Describe the solution you'd like A clear and concise description of what you want to happen.

This will allow me to define route that is opposite behaviour to my route.

i.e

if i have a preview application where it is done by header based routing like preview: pr-number, i would like to my main route to not route if that header is present i.e dont route if there is a header with key preview

Describe alternatives you've considered A clear and concise description of any alternative solutions or features you've considered.

I think the existing implementation would still work, however my suggestion would make it more explicit

Additional context Add any other context about the feature request here.