Ability to access context from serverPrefetch

[yekver]

What problem does this feature solve?

After vue 2.6 was released and serverPrefetch hook was introduces I lost a possibility to update httpCode during SSR if there was a data fetching failure.

What does the proposed API look like?

Provide access to context from the serverPrefetch hook.

[yyx990803]

We should probably provide context as the first argument. In the meanwhile you can use this.$ssrContext.