Fix various compatibility issues with PHP 8

libs/swiftmailer/classes/Swift/Events/Event.php

@@ -0,0 +1,38 @@
+<?php
+
+/*
+ * This file is part of SwiftMailer.
+ * (c) 2004-2009 Chris Corbyn
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+/**
+ * The minimum interface for an Event.
+ *
+ * @author Chris Corbyn
+ */
+interface Swift_Events_Event
+{
+    /**
+     * Get the source object of this event.
+     *
+     * @return object
+     */
+    public function getSource();
+
+    /**
+     * Prevent this Event from bubbling any further up the stack.
+     *
+     * @param bool $cancel, optional
+     */
+    public function cancelBubble($cancel = true);
+
+    /**
+     * Returns true if this Event will not bubble any further up the stack.
+     *
+     * @return bool
+     */
+    public function bubbleCancelled();
+}