lack of life cycle method `serverPrefetch` about composition-api HOT 6 CLOSED

import { createComponent, reactive, watch, onServerPrefetch } from '@vue/composition-api'
import gql from 'graphql-tag'

async function useCourses(client) {
  return client
    .query({
      query: gql`
        query getCourses {
          courses {
            id
            title
            author
            description
            topic
            url
          }
        }
      `
    })
    .then(res => res.data.courses)
}

const Courses = createComponent({
  name: 'Courses',
  components: {
    'c-course': () => import('./Course.vue')
  },

  setup(initialProps, context) {
    const { defaultClient: apolloClient } = context.root.$apolloProvider

    const state = reactive({
      courses: []
    })

    onServerPrefetch(async () => {
      // Working: the gql call is being made
      const result = await useCourses(apolloClient)
      // console.log(result)
      // Not working: Can't assign the result to state.courses
      watch(async () => {
        state.courses = result
      })
    })

    // Working: client side call and assignment
    watch(async () => {
      state.courses = await useCourses(apolloClient)
    })

    return { state }
  }
})
export default Courses