--- /dev/null
+<?php
+/**
+ * Zend Framework (http://framework.zend.com/)
+ *
+ * @link http://github.com/zendframework/zf2 for the canonical source repository
+ * @copyright Copyright (c) 2005-2015 Zend Technologies USA Inc. (http://www.zend.com)
+ * @license http://framework.zend.com/license/new-bsd New BSD License
+ */
+
+namespace Zend\Stdlib;
+
+interface MessageInterface
+{
+ /**
+ * Set metadata
+ *
+ * @param string|int|array|\Traversable $spec
+ * @param mixed $value
+ */
+ public function setMetadata($spec, $value = null);
+
+ /**
+ * Get metadata
+ *
+ * @param null|string|int $key
+ * @return mixed
+ */
+ public function getMetadata($key = null);
+
+ /**
+ * Set content
+ *
+ * @param mixed $content
+ * @return mixed
+ */
+ public function setContent($content);
+
+ /**
+ * Get content
+ *
+ * @return mixed
+ */
+ public function getContent();
+}