This is a storage engine of eventual consistency based on leveldb-1.18.
It supports many idempotent commands such as:
set,get,exists..... hget, hset, hgetall...... sadd, srem, smembers..... zadd, zrem, zrank, zscore....
and their associated data structs like: string, set, hash, zset.
The implementation of eventual consistency inspires by vector clock which is represented by a uint64_t.