private Optional<ValidationEvent> validateValidationModeMember(
            Model model,
            HttpChecksumTrait trait,
            OperationShape operation,
            StructureShape input
    ) {
        // Validate that requestValidationModeMember, which we've found already, targets a properly configured member.
        return validateEnumMember(model,
                trait,
                HttpChecksumTrait.REQUEST_VALIDATION_MODE_MEMBER,
                operation,
                input,
                trait.getRequestValidationModeMember().get(),
                HttpChecksumTrait.VALIDATION_MODES);
    }
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