protected function nackAll($requeue = false)
    {
        $delta = $this->timestampLastMessage - $this->timestampLastAck;

        $this->logger->info(sprintf(
            'Not acknowledged %d messages at %.0f msg/s',
            $this->countMessagesUnacked,
            $delta ? $this->countMessagesUnacked / $delta : 0
        ));

        $flags = Constants::AMQP_MULTIPLE;

        if ($requeue) {
            $flags |= Constants::AMQP_REQUEUE;
        }

        $this->queue->nack($this->lastDeliveryTag, $flags);
        $this->lastDeliveryTag = null;
        $this->countMessagesUnacked = 0;
    }