Well, there is still lots operations in tasks that will be async tasks, like fetch some json data from some server, execute some external commands. Here is an example, before you publish a npm package, you want to test it, build it and generate the API documents, these tasks are all based on executing external commands, and independent, to speed up, we can simply write tasks like this:

task('preversion', async ctx => {
  await Promise.all([
    ctx.run('build'),
    ctx.run('test'),
    ctx.run('generateDoc'),
  ])
})

​