What is an equivalent of `created()` in the Vue.js composition api?

Could you advise what is the equivalent of the created() in the new Vue composition API, which I'm using from within Vue2 like this:

import { reactive, toRefs } from '@vue/composition-api'

From the Composition API docs on Lifecycle Hooks:

Because setup is run around the beforeCreate and created lifecycle hooks, you do not need to explicitly define them. In other words, any code that would be written inside those hooks should be written directly in the setup function.

Anything you would have done in the created hook you can do in setup.

If you're coming from Vue 2, you can think of setup as a combination of data and created. This lends itself to elegant patterns in which data can be easily defined through a variety of means like composables, imports, etc. if desired.