public function push($item, $eta = null)
{
$eta = QueueUtils::normalizeEta($eta);
if (\Redis::SERIALIZER_NONE !== $this->redis->getOption(\Redis::OPT_SERIALIZER)) {
$item = $this->redis->_serialize($item);
}
$result = $this->redis->evaluate(self::SCRIPT_PUSH, ['items', 'seq', $item, $eta], 2);
$this->assertResult($result);
}