After posting my last Kafka transactions diary entry, JP (the Fizzbee maintainer) wrote a refactored version using non-atomic actions and a different way of representing the network. It’s a very interesting variant and I’m tempted to switch over to his version. When an action is not atomic, execution of an action could yield at any moment to a different action in a different role instance or even the same role instance. With this yielding we can also replace explicit message passing with direct invocation of a function on another node. The invocation and the response can all yield to other concurrent events happening across the system. Let me use a simple example to demonstrate - Ping-Pong.