private String getPackageName(Element element) {
        if (element instanceof PackageElement) {
            PackageElement packageElement = (PackageElement) element;
            return packageElement.getQualifiedName().toString();
        } else {
            throw new IllegalStateException("Expected Annotation to be applied to package element "
                    + "but found : " + element);
        }
    }
Maps annotation data to a plugin configuration node.

@param annotation instance of generator annotation to use to create the build config.
@return ObjectNode to use as plugin configuration node.
smithy-build/src/main/java/software/amazon/smithy/build/processor/SmithyAnnotationProcessor.java