installed plugin W3 Total Cache version 2.3.2

wp-content/plugins/w3-total-cache/lib/Azure/GuzzleHttp/Promise/PromisorInterface.php

@@ -0,0 +1,15 @@
+<?php
+namespace GuzzleHttp\Promise;
+
+/**
+ * Interface used with classes that return a promise.
+ */
+interface PromisorInterface
+{
+    /**
+     * Returns a promise.
+     *
+     * @return PromiseInterface
+     */
+    public function promise();
+}