Yes. But the Arc has to wrap a Mutex, which means you have to lock to get access. It's a dual of the Rc/RefCell/borrow mechanism.
The trouble with calling .lock() is that there is a potential for deadlock. There are some people working on static analysis for deadlock prevention, which is a dual of the static analysis for double borrow protection problem. We're maybe a PhD thesis or two from a solution. Here's some current research, out of Shanghai.[1] Outlines the theory, but code does not yet seem to be available.
