include all features of apscheduler and django-apscheduler, but more than that:
- delayed job
- cron
- interval until
- once at
- distributed deploy with etcd
- less db pressure
- interval-job 中暂不支持 start_time~end_time区间执行。暂时没遇到这种情况
- interval-job,cron-job的 start_immediately 暂不支持
- 根据log要求记录到db
- 根据django配置决定线程
- missed的情况要根据历史记录
- 合并执行 collease
- 并行度 mx_instance
- 事务性 delayedjob