Decoupled ID types
Enhancements:
It is now possible to use different types for the event id, and the stream ids.
Usually, you'll want something like long or Guid for your event ids, but the stream id is not so rigid - it might make sense to use a string built from the aggregate type and id, for example. But since string is probably not a good choice of PK for the event table, they are now completely decoupled.