code: func (db *DB) storeUint64(key []byte, n uint64) error {
  	blob := make([]byte, binary.MaxVarintLen64)
  	blob = blob[:binary.PutUvarint(blob, n)]
  	return db.lvl.Put(key, blob, nil)
  }
docs: // storeUint64 stores an integer in the given key.