Produced MIME type declaration not honoured in reactive routes

[jponge]

With Quarkus 1.6.1.Final and the following reactive routes code:

@ApplicationScoped
public class Routes {

    @Route(methods = HttpMethod.GET, path = "/hello", produces = "text/plain")
    void hello(RoutingContext context) {
        context.response().end("hello");
    }

    @Route(methods = HttpMethod.GET, path = "/hi/:name", produces = "application/json")
    void hi(RoutingExchange routing) {
        String name = routing.getParam("name").orElse("what?");
        routing.ok(new JsonObject()
                .put("name", name)
                .put("timestamp", System.currentTimeMillis()).encode());
    }
}

then the produced MIME content is not honoured (the Content-Type header is missing), see:

$ http :8080/hi/mrbean
HTTP/1.1 200 OK
content-length: 43

{"name":"mrbean","timestamp":1595608877519}

and:

$ http :8080/hello
HTTP/1.1 200 OK
content-length: 5

hello