code: func (g *Graceful) Run() {
  	env := g.Env
  	if env == nil {
  		env = defaultEnv
  	}
  
  	// prepare listener files
  	listeners, err := g.Listen()
  	if err != nil {
  		env.Cancel(err)
  		return
  	}
  	g.Serve(listeners)
  }
docs: // Run simply calls g.Listen then g.Serve on Windows.