When using the SimpleEventScheduler, it is not possible to store the sagas in the JpaSagaRepository (or any other persistent store). This is due to the SimpleScheduleToken, which contains a Future.
Instead, the Scheduler should keep a Map of ID to Future of all the tasks. The ID can be a randomly generated string, and is serializable. The future would allow the scheduler to cancel a schedule.
Ensured that the scheduletoken is serializable (#28)
The ScheduleToken now only contains a String, which references the