+ /**
+ * @param $casToken mixed
+ * @param $key string
+ * @param $value mixed
+ * @param $exptime int
+ * @return bool
+ */
+ function cas( $casToken, $key, $value, $exptime = 0 ) {
+ if ( $this->get( $key ) === $casToken ) {
+ return $this->set( $key, $value, $exptime );
+ }
+
+ return false;
+ }
+
+ /**
+ * @param $key string
+ * @param $time int
+ * @return bool
+ */