code: func (e *EncryptedRaftLogger) SaveEntries(st raftpb.HardState, entries []raftpb.Entry) error {
  	e.encoderMu.RLock()
  	defer e.encoderMu.RUnlock()
  
  	if e.wal == nil {
  		return fmt.Errorf("raft WAL has either been closed or has never been created")
  	}
  	return e.wal.Save(st, entries)
  }
docs: // SaveEntries saves only entries to disk