code: func (mvcc *MVCCLevelDB) RawGet(key []byte) []byte {
  	mvcc.mu.Lock()
  	defer mvcc.mu.Unlock()
  
  	ret, err := mvcc.db.Get(key, nil)
  	terror.Log(err)
  	return ret
  }
docs: // RawGet implements the RawKV interface.