> This is in contrast to the fact that Go's cheap threading means that you don't need to colour your functions with async or not async. But this quote that you sort of have to do this with context or no context.

This doesn't have the usual problems associated with colored functions though (ie, calling async functions from non-async functions or vice-versa). If you don't need cancellation, pass a `context.Background()` and you're done.

> If goroutines are so cheap then why not let the library spawn them. As long as the interface doesn't reveal if they are being used or not it shouldn't matter.

Agreed. providing a synchronous API is what's important.