How can I Validate a value rather than capturing it, think x-api-key header

[nicktrienensfuzz]

I'm looking to check a value inside the route block rather than capturing the value, is there a function to allow this?

Headers {
    Field("x-api-key", "123").equals("123")
}

enum AppRoute {
    case books
 }
        
let appRouter = OneOf {
   // GET /books
   Route(.case(AppRoute.books)) {
      Headers {
          Field("x-api-key", "123").equals("123")
         }
       Path { "books" }
    }
}