How to cancel a transition in callback?

[wenchaoliao]

I use the CancelTransition method and want to cancel a transition while do some thing failed in the callback , but it complain event run1 inappropriate because previous transition did not complete after I cancel the transition and input a new event.

func main() {
	f := fsm.NewFSM(
		"start",
		fsm.Events{
			{Name: "run_async", Src: []string{"start"}, Dst: "end"},
			{Name: "run", Src: []string{"start"}, Dst: "end"},
		},
		fsm.Callbacks{
			"leave_start": func(_ context.Context, e *fsm.Event) {
				if e.Event == "run_async" {
					e.Async()
				}
			},
		},
	)

	err := f.Event(context.Background(), "run_async")

	asyncError, ok := err.(fsm.AsyncError)
	if !ok {
		panic("!ok")
	}
      //do something failed
	asyncError.CancelTransition()

	if err := f.Transition(); err != nil {
		panic(fmt.Sprintf("Transition err:%v", err))
	}

	if err := f.Event(context.Background(), "run"); err != nil {
		panic(fmt.Sprintf("run event err:%v", err))
	}
}

it complain panic: run event err:event run inappropriate because previous transition did not complete