When designing an API with a suspend function, sometimes I want to convey that this function should be called on, say, an IO thread. Other times that it is essential to do so.
Often it seems obvious; for example a database call should be called using Dispatchers.IO but if it's an interface function, then the caller cannot assume this.
What is the best approach here?
If the suspend function really must run in a specific context, then declare it directly in the function body.
suspend fun doInIO() = withContext(Dispatchers.IO) {
}
If the caller should be able to change the dispatcher, the function can add the dispatcher as a default parameter.
suspend fun doInIO(context: CoroutineContext = Dispatchers.IO) = withContext(context) {
}