面试题：在分布式系统，你能想出来几种生成唯一ID的方案？(13)_系统唯一ID是我们在设计一个系统的时候

throw new ApplicationException(string.Format(\"Clock moved backwards. Refusing to generate id for %d milliseconds\" lastTimestamp - timestamp));

if (lastTimestamp == timestamp)
{
sequence = (sequence + 1) & sequenceMask;
if (sequence == 0)
{
timestamp = tilNextMillis(lastTimestamp);

else