Async Transformers

I was using Compiler API and basically changed program.emit at host.afterProgramCreate just like examples and hooked my transformers into emit function. But one thing i couldn't find anywhere is a async transformer. Im using PostCSS and some other stuff like that and implementing those to a single typescript compiler but some plugins are async in postcss and i cant use them at the moment. Is there any way to implement this that im missing or undocumented ? And in case somebody offers to use webpack my code is mostly javascript based and i need really good static analysis for it with type data included that's also reason i use typescript's api instead of using babel which have those cases mostly covered with plugins. I'm implementing all-in-one solution for my company/community project so ideally it needs to be inside typescript compiler.

Beginne mit den im Issue genannten Einstiegspunkten der Compiler API: program.emit und host.afterProgramCreate, und vergleiche dann den Transformer-Lebenszyklus mit den beteiligten asynchronen PostCSS-Plugins. Als erledigt gilt, festzustellen, ob asynchrone Transformer unterstützt werden, oder eine konkrete, klar abgegrenzte Compiler-Änderung zu dokumentieren, die erforderlich ist, um sie zu unterstützen.