async function async1(){
        console.log('async1 start');
        await async2();
        console.log('async1 end');
    }
    async function async2(){
        console.log('async2');
    }
    console.log('script start');
    setTimeout(function(){
        console.log('setTimeout')
    },0)
    async1();
    new Promise(function(resolve){
        console.log('promise1');
        resolve();
    }).then(function(){
        console.log('promise2');
    })
    console.log('script end')