public void setJsonContentType(String jsonContentType) {
        this.jsonContentType = Objects.requireNonNull(jsonContentType);
    }
Sets a custom media-type to associate with the JSON payload of
JSON-based protocols.

@param jsonContentType Content-Type to use for JSON protocols by default.
smithy-openapi/src/main/java/software/amazon/smithy/openapi/OpenApiConfig.java