@Override
    public SecurityScheme createSecurityScheme(Context<? extends Trait> context, SigV4Trait trait) {
        return SecurityScheme.builder()
                .type("apiKey")
                .description("AWS Signature Version 4 authentication")
                .name(AUTH_HEADER)
                .in("header")
                .putExtension("x-amazon-apigateway-authtype", Node.from("awsSigv4"))
                .build();
    }
Adds AWS signature version in a way that"s compatible with AWS API Gateway.
smithy-openapi/src/main/java/software/amazon/smithy/openapi/fromsmithy/security/AwsV4Converter.java