@Override
    public List<ValidationEvent> validate(Model model) {
        ArnIndex arnIndex = ArnIndex.of(model);
        List<ValidationEvent> events = new ArrayList<>();
        for (ServiceShape service : model.getServiceShapesWithTrait(ServiceTrait.class)) {
            events.addAll(validateService(model, arnIndex, service));
        }
        return events;
    }
Ensures that all arn traits for a service are valid and that their templates
only reference valid resource identifiers.
smithy-aws-traits/src/main/java/software/amazon/smithy/aws/traits/ArnTemplateValidator.java