app.use((ctx,next) => { console.log(1) next() console.log(2) }) app.use(async (ctx,next) => { console.log(3) const axios  = require('axios'); const res = await axios.get('http://baidu.com') console.log(4) })Copy the code

If we do not await the Onion model (no await before next()), we will execute 1, 3, 2, 4, and we want to execute 2 after 4 so the Onion model guarantees the order of execution