A few samples, notably DiningPhilosophers and ProducerConsumer are actually testing for multi-actor deadlock. It is now faked by using the @Arbiter and default (continuous) mode, but it comes with a few drawbacks.

First, it is kludgy. Second, that mode runs @Actor once per @State, and so deadlock opportunity is rather narrow.

Instead, we should be having a special deadlock mode.