深度理解nodejs[3]—疯狂事件代码

const https = require('https');
const start = Date.now();
const fs = require('fs');
const crypto = require('crypto');
function dorequest(){
  https.request('https://www.baidu.com',res=>{
    res.on('data',()=>{});
    res.on('end',()=>{
      console.log(Date.now()-start);
    });
  })
  .end();
}


function dohash(){
  crypto.pbkdf2('a','b',100000,512,'sha512',()=>{
    console.log('hash:',Date.now()-start);
  });
}

dorequest();

fs.readFile('test.js','utf8',()=>{
  console.log('FS:',Date.now()-start);
});
dohash();
dohash();
dohash();
dohash();

42
hash: 785
FS: 785
hash: 788
hash: 790
hash: 790