如何利用vue-cli监测webpack打包与启动时长

"scripts": {
    "serve": "vue-cli-service serve",
    "build": "vue-cli-service build",
    "lint": "vue-cli-service lint"
},

// 开始时间
let startTime = '';
async function build(args, api, options) {
	startTime = Date.parse(new Date())
    ...// other code
    return new Promise((resolve, reject) => {
        ...// other code
        if (args.target === 'app' && !isLegacyBuild) {
          if (!args.watch) {
            console.log('结束时间戳：'+Date.parse(new Date()))
            console.log('花费时间：'+(Date.parse(new Date())-startTime)/1000+'秒')
            done(`Build complete. The ${chalk.cyan(targetDirShort)} directory is ready to be deployed.`)
            info(`Check out deployment instructions at ${chalk.cyan(`https://cli.vuejs.org/guide/deployment.html`)}\n`)
          } else {
            done(`Build complete. Watching for changes...`)
          }
        }
        ...// other code
    })
}

let startTime = '';
async function serve(args) {
	//开始时间
    startTime = Date.parse(new Date());
    ...// other code
    return new Promise((resolve, reject) => {
        // log instructions & open browser on first compilation complete
      	let isFirstCompile = true
        compiler.hooks.done.tap('vue-cli-service serve', stats => {
            ...// other code
            console.log(`  App running at:`)
            console.log(`  - Local:   ${chalk.cyan(urls.localUrlForTerminal)} ${copied}`)
            console.log('结束时间戳：' + Date.parse(new Date()))
            console.log('花费时间：' + (Date.parse(new Date()) - startTime) / 1000 + '秒')
            ...// other code
        }
    })
}

let startTime = '';
async function serve(args) {
	//开始时间
    startTime = Date.parse(new Date());
    ...// other code
    return new Promise((resolve, reject) => {
        // log instructions & open browser on first compilation complete
      	let isFirstCompile = true
        compiler.hooks.watchRun.tap('vue-cli-service serve', compiler => {
            if (!isFirstCompile) {
              console.log('...starting..................')
              startTime = Date.parse(new Date());
            }
          })
        compiler.hooks.done.tap('vue-cli-service serve', stats => {
            ...// other code
            console.log(`  App running at:`)
            console.log(`  - Local:   ${chalk.cyan(urls.localUrlForTerminal)} ${copied}`)
            console.log('结束时间戳：' + Date.parse(new Date()))
            console.log('花费时间：' + (Date.parse(new Date()) - startTime) / 1000 + '秒')
            ...// other code
        }
    })
}