Fix various compatibility issues with PHP 8

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

@@ -0,0 +1,27 @@
+<?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.
+ */
+
+/**
+ * Generated when the state of a Transport is changed (i.e. stopped/started).
+ *
+ * @author Chris Corbyn
+ */
+class Swift_Events_TransportChangeEvent extends Swift_Events_EventObject
+{
+    /**
+     * Get the Transport.
+     *
+     * @return Swift_Transport
+     */
+    public function getTransport()
+    {
+        return $this->getSource();
+    }
+}