A future is a simple blocking mechanism. The Scala example above uses something called a future, but isn't. It's an "Rx" functional future – cool and often useful, but it's yet another construct that isn't part of the actor model. I'm happy to use Rx, but I wouldn't use it in an actor.

There are many ways to tackle concurrency, but IMO it's best to keep them separate as much as possible, or you quickly lose track of what's happening when.