text: let Koa = require('./08.my-koa')
  // let Koa = require('koa')
  let app = new Koa()
  
  app.use(async (ctx, next) => {
    console.log(1);
    await next()
    console.log('final');
  })
  
  
  app.use(async (ctx, next) => {
    console.log(2);
    await next()
    console.log(4);
  })
  
  app.use(async (ctx, next) => {
    console.log(3);
    ctx.res.end('OK')
  })
  
  app.listen(8080)