Create a possibility to work with aggregates having immutable identifier (e.g. data class with a val)

[zambrovski]

Kotlin immutability is a strong feature. Based on Java implementation, aggregates members have to be mutable, to be able to get modified from the event sourcing handlers (including the aggregate identifier).

As shown on Event-Driven-Microservices 2019 conference, this can be changed (shown in Scala) by providing a special aggregate factory, which creates aggregates with at least immutable aggregate identifier.

[zambrovski]

I have a running implementation on that. Thanks to Jan-Hendrick scala pitch...

[jangalinski]

Then we have to re-record that part of our presentation ... :-)

[smcvb]

Adjusted the milestone of this issue, and the pull request, to 0.3.0.
I have done this in favor of doing a Kotlin Extension release once more.

[zambrovski]

Do you think it is required to split the PR into non-spring only and spring config by any means? Is it possible to discuss missing features in the Spring-part instead?

[smcvb]

I've left a more thorough comment on the pull request just now! Let me know what you think @zambrovski.