@Override
    public List<ValidationEvent> validate(Model model) {
        List<ValidationEvent> events = new ArrayList<>();

        for (OperationShape operation : model.getOperationShapesWithTrait(HttpChecksumTrait.class)) {
            events.addAll(validateOperation(model, operation));
        }

        return events;
    }
Validates the HttpChecksum trait.

<ul>
    <li>Validates that at least one of the request or response checksum
    behavior is configured.</li>
    <li>Validates that the {@code requestAlgorithmMember} and
    {@code requestChecksumModeMember} properties point to valid input members.</li>
    <li>Validates that the {@code requestAlgorithmMember} targeted member contains
    only supported algorithms.</li>
    <li>Validates that the {@code requestChecksumModeMember} targeted member contains
    only supported modes.</li>
    <li>Checks for conflicts with {@code @httpHeader} and {@code @httpPrefixHeaders}.</li>
</ul>
smithy-aws-traits/src/main/java/software/amazon/smithy/aws/traits/HttpChecksumTraitValidator.java