Coroutines

but what are implementations of blocking File IO which should be run in a coroutine?

Not sure if I understand what you are asking, but if you use the Dispatchers.IO context that should work for you

You take the blocking IO stuff like read the contents of a file and execute inside of the Dispatchers.IO context using

withContext(<http://Dispatchers.IO|Dispatchers.IO>) { }

. And then you just program your asynchronous code like you would with coroutines.

https://github.com/Kotlin/coroutines-examples/blob/master/examples/sequence/sequenceOfLines.kt This is an example of reading lines with suspending functions. Basically you read a line and yield to let other coroutines do their job instead of reading everything in one go.