@Override
    public List<ValidationEvent> validate(Model model) {
        List<ValidationEvent> events = new ArrayList<>();
        for (MemberShape member : model.getMemberShapesWithTrait(HttpPrefixHeadersTrait.class)) {
            model.getShape(member.getContainer()).flatMap(Shape::asStructureShape).ifPresent(structure -> {
                events.addAll(validateMember(structure, member, member.expectTrait(HttpPrefixHeadersTrait.class)));
            });
        }

        return events;
    }
Validates that httpHeader traits do not case-insensitively start with an
httpPrefixHeader on the same structure.
smithy-model/src/main/java/software/amazon/smithy/model/validation/validators/HttpPrefixHeadersTraitValidator.java