I'm exploring Event Carried State Transfer patter, I understand how it works, but there is one problem I don't know how to solve.
So, in ECST, a service can listen to events and then build a private state from those events. As an example - let's say I have a User service and my service consumer CRUD-like user-related events to build a private state about the users I need in my service. I can nicely update that state when I receive an event - but how can I bootstrap the state of my service with data that already existed before I released my service?
The simplest idea is to have an API that the service can query to fetch all users, but that sounds nor right as it couples the consumer with the producer.