＊＊ In order to observe the effect of experiment in a better way, you should turn on the network tab of console ＊＊

1. send a http request(ps：set the timeout config as 5s, the timeout msgs will be shown in console)

2. send a http request to get a local file(ps:，an invitably successful request, the loading style flashes out on the screen)

3. send an excluded http request（ps：Because the request has been excluded, the loading style will not be shown）