code: protected function setValues($data, $duration)
      {
          if ($this->useMemcached) {
              // Use UNIX timestamp since it doesn't have any limitation
              // @see https://secure.php.net/manual/en/memcache.set.php
              // @see https://secure.php.net/manual/en/memcached.expiration.php
              $expire = $duration > 0 ? $duration + time() : 0;
  
              // Memcached::setMulti() returns boolean
              // @see https://secure.php.net/manual/en/memcached.setmulti.php
              return $this->_cache->setMulti($data, $expire) ? [] : array_keys($data);
          }
  
          return parent::setValues($data, $duration);
      }
docs: Stores multiple key-value pairs in cache.
  @param array $data array where key corresponds to cache key while value is the value stored
  @param int $duration the number of seconds in which the cached values will expire. 0 means never expire.
  @return array array of failed keys.