public function flushPipeline($send = true)
    {
        if ($send && !$this->pipeline->isEmpty()) {
            $responses = $this->executePipeline($this->getConnection(), $this->pipeline);
            $this->responses = array_merge($this->responses, $responses);
        } else {
            $this->pipeline = new \SplQueue();
        }

        return $this;
    }