RocksDB checkpoint support

[elrik75]

Hi! I think RocksDict doesn't support checkpoints https://github.com/facebook/rocksdb/wiki/Checkpoints
Checkpoints are used to quickly create backups of the DB. I think it's a key feature.
Is it possible? If not, is this planned for later?
Thank you.

[Congyuwang]

I think we can probably have this. You can open an issue for it.