code: func (db *DB) Dump(key []byte) ([]byte, error) {
  	v, err := db.Get(key)
  	if err != nil {
  		return nil, err
  	} else if v == nil {
  		return nil, err
  	}
  
  	return rdb.Dump(rdb.String(v))
  }
docs: /*
     To support redis <-> ledisdb, the dump value format is the same as redis.
     We will not support bitmap, and may add bit operations for kv later.
  
     But you must know that we use int64 for zset score, not double.
     Only support rdb version 6.
  */
  // Dump dumps the KV value of key