can I write a function, that could be used both in...

# coroutines

[rrva]

can I write a function, that could be used both in a coroutine context, and outside of a coroutine context, with a single signature, perhaps using an optional Continuation parameter?

[elizarov]

Only inline higher-order functions can do that, but if you need a Continuation, then it will have to be a suspending function.