jobManage cpCondate – 触发 --> taskManage: traginCheckpoint --> source --> emit branine --> opetatte: branie对齐 == snapshotState ==持久化到backend --> 返回 stateHadle到 jobmange --> 继续下一个算子 brain对齐，shnaspshotState，ack JM – … --> sink
checkpoint两阶段提交
checkPonitLisen
等待所有算子state shnapshot完成并持久化到backend 并 ack JM ， JM 收到所有算子 stateshop 完成后触发 notifyComplie
savepoint
at most once
at last once
exactly once
e2e exactly
