Low-level, not medium- or high-level

The aim is that the cost of a deferred inter-actor call should be on the order of a normal direct inter-object call. Obviously we can never as low as a direct call, but we want to get as close as possible. This means that Stakker is not aiming to replace multi-threaded asynchronous runtimes, multi-threaded asynchronous message systems, inter-thread channels, distributed systems, or anything else like that.

Rather Stakker's aim is to replace a mess of Rc<RefCell<...>> and a tangle of direct and indirect inter-object calls (or any other improvised collection of communicating components in the same thread) with a nice ordered, well-behaved set of actors, easy to reason about and maintain.

Higher-level inter-thread load balancing, work distribution and message passing can be layered on top of Stakker as necessary.