asyncComputed return only default value

Please explain to me why when I run this code I get the default value:
`Vue.use(AsyncComputed);
export default {
  asyncComputed: {
    a: {
      get() {
        return 1;
      },
      default() {
        return 0;
      }
   },
  mounted() {
    console.log(this.a)
  }
}
`

I apologize for the unformed code. For some reason, the code insertion does not work.