code: func handleSignal(env *Environment) {
  	ch := make(chan os.Signal, 2)
  	signal.Notify(ch, stopSignals...)
  
  	go func() {
  		s := <-ch
  		log.Warn("well: got signal", map[string]interface{}{
  			"signal": s.String(),
  		})
  		env.Cancel(errSignaled)
  	}()
  }
docs: // handleSignal runs independent goroutine to cancel an environment.