@Override
    protected Node createNode() {
        return new ObjectNode(MapUtils.of(), getSourceLocation())
                .withMember("uri", Node.from(uri))
                .withOptionalMember("prefix", getPrefix().map(Node::from));
    }
Defines the XML Namespace prefix and URI.
smithy-model/src/main/java/software/amazon/smithy/model/traits/XmlNamespaceTrait.java