添加getBy方法

@@ -122,6 +122,11 @@ class Memcache extends Root implements CacheInterface
         return $this->init()->get($this->_makeTag() . $key, $flags);
     }
 
+    public function getBy($key, $cacheCb = null, &$casToken = null)
+    {
+        return $this->init()->get($key, $cacheCb, $casToken);
+    }
+
     /**
      *  向一个新的key下面增加一个元素
      * @param $key

@@ -167,6 +167,11 @@ class Memcached extends Root implements CacheInterface
         return $this->init()->get($this->_makeTag() . $key, $cacheCb, $casToken);
     }
 
+    public function getBy($key, $cacheCb = null, &$casToken = null)
+    {
+        return $this->init()->get($key, $cacheCb, $casToken);
+    }
+
     /**
      *  向一个新的key下面增加一个元素
      * @param $key