File: //usr/share/doc/cpanel-php84-xml-serializer/examples/serializeWithComment.php
<?PHP
/**
 * This is just a basic example that shows
 * how objects can be serialized so they can
 * be fully restored later.
 *
 * @author Stephan Schmidt <schst@php.net>
 */
error_reporting(E_ALL);
require_once 'XML/Serializer.php';
$options = array(
                    XML_SERIALIZER_OPTION_INDENT      => '    ',
                    XML_SERIALIZER_OPTION_LINEBREAKS  => "\n",
                    XML_SERIALIZER_OPTION_COMMENT_KEY => 'comment'
                );
$foo = new stdClass;
$foo->comment = 'This is a comment';
$foo->value   = 'My value';
$foo->bar     = new stdClass();
$foo->bar->value   = 'Another value';
$foo->bar->comment = 'Another comment';
$foo->tomato          = new stdClass();
$foo->tomato->comment = 'And a last comment';
$serializer = &new XML_Serializer($options);
$result = $serializer->serialize($foo);
if ($result === true) {
    $xml = $serializer->getSerializedData();
}
echo '<pre>';
echo htmlspecialchars($xml);
echo '</pre>';
?>