public function flush($force = false, $key = null)
    {
        if (! isset($this->flushed[$key]) && ($force || $this->needsToFlush())) {
            try {
                $this->forceFlush($key);
            } catch (Exception $exception) {
                report($exception);
            }

            $this->flushed[$key] = true;
        }
    }