code: func NewMirrorWriter() *MirrorWriter {
  	mw := &MirrorWriter{
  		msgSync:   make(chan []byte, 64), // sufficiently large buffer to avoid callers waiting
  		writerAdd: make(chan *writerAdd),
  	}
  
  	go mw.logRoutine()
  
  	return mw
  }
docs: // NewMirrorWriter initializes and returns a MirrorWriter.