src/main/java/com/github/oxo42/stateless4j/StateConfiguration.java
public StateConfiguration<S, T> onExit(Action1<Transition<S, T>> exitAction) {
        assert exitAction != null : EXIT_ACTION_IS_NULL;
        representation.addExitAction(exitAction);
        return this;
    }
public StateConfiguration<S, T> onExit(Action1<Transition<S, T>> exitAction) {
        assert exitAction != null : EXIT_ACTION_IS_NULL;
        representation.addExitAction(exitAction);
        return this;
    }
Specify an action that will execute when transitioning from the configured state

@param exitAction Action to execute
@return The receiver