Error handling on quarkus mutiny rest client

On my quarkus rest project i have a restclient that uses mutiny:

@Path("/")
@RegisterRestClient(configKey = "my-api")
@RegisterClientHeaders
@RegisterProvider(MyExceptionMapper.class)
public interface MyClient {

  @POST
  @Path("path")
  Uni<MyBean> get(String body);
}

I wanna handle propery non 2XX httpError so i have made my ExceptionMaper

public class MyExceptionMapper implements ResponseExceptionMapper<MyException> {
  @Override
  public MyException toThrowable(Response response) {
    //TODO
    return new MyException();
  }
}

a bad call on the client shows that MyExceptionMapper handle the response but the exception raises and does not became a failure on my Uni Client response object

Uni<MyBean> bean = myClient.get("") // i do not have a failure in case of 4XX http 
   .onFailure().invoke(fail -> System.out.println("how can i get here?"));

Am i using mutiny on a rest client in the wrong way?

Thanks

UPDATE

ok i forgot to add the dependency quarkus-rest-client-mutiny, adding this i notice 2 things,

• i still pass through Myexceptionmapper

• i also produce a Uni.failure, but the exception into the failure is not the custom exception i created into MyExceptionmapper but a RestEasyWebApplicationException

  Failure : org.jboss.resteasy.client.exception.ResteasyWebApplicationException: Unknown error, status code 400 at org.jboss.resteasy.client.exception.WebApplicationExceptionWrapper.wrap(WebApplicationExceptionWrapper.java:107) at org.jboss.resteasy.microprofile.client.DefaultResponseExceptionMapper.toThrowable(DefaultResponseExceptionMapper.java:21)

Does the ExceptionMapper becomes useless in this context?