vendor and env first commit

vendor/psr/event-dispatcher/src/EventDispatcherInterface.php

@@ -0,0 +1,21 @@
+<?php
+declare(strict_types=1);
+
+namespace Psr\EventDispatcher;
+
+/**
+ * Defines a dispatcher for events.
+ */
+interface EventDispatcherInterface
+{
+    /**
+     * Provide all relevant listeners with an event to process.
+     *
+     * @param object $event
+     *   The object to process.
+     *
+     * @return object
+     *   The Event that was passed, now modified by listeners.
+     */
+    public function dispatch(object $event);
+}