+ /**
+ * @param $key string
+ * @param $callback closure Callback method to be executed
+ * @param $exptime int Either an interval in seconds or a unix timestamp for expiry
+ * @param $attempts int The amount of times to attempt a merge in case of failure
+ * @return bool success
+ */
+ public function merge( $key, closure $callback, $exptime = 0, $attempts = 10 ) {
+ return $this->doWrite( 'merge', $key, $callback, $exptime );
+ }
+