+ /**
+ * Perform a HEAD request against the endpoint's underlying URL
+ *
+ * @param mixed $args The HTTP query string parameters
+ * @param array $headers The request's additional HTTP headers
+ * @return mixed promise
+ */
+ function head($args = null, array $headers = null, $cache = null) {
+ return $this->request("HEAD", $args, null, $headers, $cache);
+ }
+