legacy/web/src/main/java/org/jboss/as/web/WebSubsystemParser.java
private boolean writeAttribute(XMLExtendedStreamWriter writer, SimpleAttributeDefinition attribute, ModelNode node,
                                   boolean startWriten, String origin) throws XMLStreamException {

        if (attribute.isMarshallable(node, false)) {
            if (!startWriten) {
                startWriten = true;
                writer.writeStartElement(origin);
            }
            attribute.marshallAsAttribute(node, false, writer);
        }
        return startWriten;
    }
private boolean writeAttribute(XMLExtendedStreamWriter writer, SimpleAttributeDefinition attribute, ModelNode node,
                                   boolean startWriten, String origin) throws XMLStreamException {

        if (attribute.isMarshallable(node, false)) {
            if (!startWriten) {
                startWriten = true;
                writer.writeStartElement(origin);
            }
            attribute.marshallAsAttribute(node, false, writer);
        }
        return startWriten;
    }
todo, attribute.marshallAsAttribute should return boolean