aphrodite.StyleSheetServer is null creating a static page

Upgrading from `1.2.5` into `2.2.3` I am getting this error while I create an `html` page on-the-fly to be _downloaded_.

Seems that [this check](https://github.com/Khan/aphrodite/blob/84e0a72ce20d77c8d5481f1509ece86ffa704515/src/exports.js#L74) doesn't pass and it's correct since the page generation happens in the browser, but it is a _static_ page generation.

Is there a new way to approach this in `aphrodite@^2`?

Begin with src/exports.js at the linked check and reproduce the static HTML download flow while comparing Aphrodite 1.2.5 and 2.2.3 behavior. Determine whether version 2 documents or supports this browser-side static-generation path; done means a confirmed supported approach or a precisely scoped fix with a regression test.

Written by the indexing model from the issue text.