[dhosek]

The other problem with the parallel streams is that it’s badly implemented. Threads for parallel streams are pulled from a single thread pool shared across the whole application so if you have multiple parallel streams in an application that’s already inherently multithreaded (e.g. a web service), you end up with severe resource contention that makes the parallelism work poorly if at all and can end up causing your app to deadlock because all the threads are in use somewhere else. There’s a workaround for it, but it ends up requiring some ugly boilerplate code to work.