code: func (t TeeType) Writer() io.Writer {
  	switch t {
  	case TeeNone:
  		return nil
  
  	case TeeStdout:
  		return os.Stdout
  
  	case TeeStderr:
  		return os.Stderr
  
  	default:
  		panic(fmt.Errorf("streamproto: unknown tee type [%v]", t))
  	}
  }
docs: // Writer returns the io.Writer object