public function getTimeSleepUntil()
    {
        if ($this->delay == 0) {
            return 0;
        }
        $query = $this->pdo->prepare(<<<SQL
SELECT
  delayUntil,
  UNIX_TIMESTAMP()
FROM robotstxt__delay0
WHERE base = :base AND userAgent = :userAgent;
SQL
        );
        $query->bindValue('base', $this->base, \PDO::PARAM_STR);
        $query->bindValue('userAgent', $this->userAgent, \PDO::PARAM_STR);
        $query->execute();
        $this->increment();
        if ($query->rowCount() > 0) {
            $row = $query->fetch(\PDO::FETCH_ASSOC);
            $this->clockSyncCheck($row['UNIX_TIMESTAMP()'], self::OUT_OF_SYNC_TIME_LIMIT);
            return $row['delayUntil'] / 1000000;
        }
        return 0;
    }