## write failure when switch ledger error
often fail during switch!because it try to write closed ledger, because not sync on ledger!!
多线程编程时注意确保状态切换导致的不一致
## write failure when switch ledger error
often fail during switch!because it try to write closed ledger, because not sync on ledger!!
多线程编程时注意确保状态切换导致的不一致