Hello, tutorials on kotlin describe using suspendC...

# coroutines

[hmgeorge]

Hello, tutorials on kotlin describe using suspendCoroutine
or suspendCancelableCoroutine as the recommended
way to deal with external libraries that provide a callback interface.
However, most examples given seem to be for one shot
results, e.g. make a network request and wait for the result.
What would be the idiomatic way to handle interactions
with external libraries that provide a listener interface.
e.g. FileObserver on Android where we register to observe
changes but we do not know when the callback will be
issued. Is using Continuation<T> an acceptable method?
E.g. https://gist.github.com/hmgeorge/1e5ee34265d5154e05251c1287843515 . or is using a Channel preferred?

[streetsofboston]

A Continuation is like a Single or Rx. You can continue (normally or with an error) only once. If you try more than once, you'll get an error.
For a continuous callback, use a Channel whose send or offer is called on each callback. Start it within a Job (e.g use launch). Be sure to de-register your callback listener when this Job finishes/cancels.

[hmgeorge]

thanks for the reply .. question though .

[hmgeorge]

You can continue (normally or with an error) only once.

[hmgeorge]

I thought continuations can be saved and resumed upon multiple times, (for e.g in the case of scheme call/cc) . the gist i provided works without exceptions as well.