Control.Concurrent.PooledIO.Independent

Execute all actions parallelly but run at most numCapabilities threads at once. Stop when all actions are finished. If a thread throws an exception this terminates only the throwing thread.

Execute all actions parallelly without a bound an the number of threads. Stop when all actions are finished.

If a thread ends with an exception, then terminate all threads and forward that exception. runException Nothing chooses to use all capabilities, whereas runException (Just n) chooses n capabilities.