ServerHeadersDsl doesn't allow addition of custom ServerHttpHeadersWriter

[vonZeppelin]

Expected Behavior
It should be possible to add a custom ServerHttpHeadersWriter with Kotlin DSL, something like

http {
    headers {
        writer {
            StaticServerHttpHeadersWriter.builder()
                .header(..., ...)
                .build()
        }
    }
}

Current Behavior
Kotlin ServerHeadersDsl class doesn't provide a way to add custom ServerHttpHeadersWriters.

Context
A workaround is

http.headers { spec ->
    spec.writer(...)
}

[evgeniycheban]

Hi, @jzheaux since gh-16002 was closed due to being fixed by spring-framework team, I could take this instead.