How to make callbackFlows main-safe?

Question

In my ViewModel I have to call a repository function that exposes a callbackFlow.

Normally I would have the suspend function in repo classes wrap their code block in a withContext(Dispatcher.IO) { } block. Or if I want to make a Flow main-safe I could also use the .flowOn() operator, but that api isn't available with callbackFlows.

So my question is 'how do I make the use of callbackFlows main-safe?'... assuming they aren't out of the box.