Async iterable support?

[vaultec81]

I think it would be a good idea to include async iterable function support along with regular async function. An example of use case would be streaming large amounts of data from the main process to the renderer process for display. Async iterables are especially important to keep memory usage low when sending large amounts of data between main and renderer process.

[sibnerian]

Sounds like a great addition, looking forward to your PR :)