Tue Jan 28 07:28:34 EST 2020

Practical example

I don't think this can be abstracted away, as it is a core part of how
the two machines perform transitions in the presence of other things
going on.  So the transaction is an essential part of the machine's
main transition function.

An example.  Two machines:
1. writer is a counter that writes out the next state
2. reader is synchronized to an external pulse

Ok that's some setup to start with.