It's clear, that when we call `fetch` on an instance of `RemoteRef`, it blocks the task. But does it mean that the whole thread is blocked (and thus we experience thread context switching) or control is simply passed to another task?
For context: I'm trying to understand different ways of asynchronous programming in Julia. I see that Julia Tasks reflect actor model pretty well. But I'm curious if they also may be used as Future-like objects. With Futures (as implemented, for example, in Finagle [1]), I can specify `onSuccess` and `onFailure` callbacks to process result when it is ready. Julia doesn't seem to support these semantics, so I'd like to know the proper way (i.e. the way that doesn't block the thread) of using tasks/fetch/wait with the same purpose. [1]: http://twitter.github.io/finagle/guide/Futures.html
