private Optional<String> binaryMediaType(Model model, Map<String, HttpBinding> httpBindings) {
        return httpBindings.values()
                .stream()
                .filter(binding -> binding.getLocation().equals(HttpBinding.Location.PAYLOAD))
                .map(HttpBinding::getMember)
                .flatMap(member -> OptionalUtils.stream(member.getMemberTrait(model, MediaTypeTrait.class)))
                .map(MediaTypeTrait::getValue)
                .findFirst();
    }
Adds API Gateway binary media types as a top-level key in the OpenAPI model
named {@code x-amazon-apigateway-binary-media-types}.

<p>This data is used by API Gateway to determine which content-types do
not contain UTF-8 data.
smithy-aws-apigateway-openapi/src/main/java/software/amazon/smithy/aws/apigateway/openapi/AddBinaryTypes.java