Annotation that attaches revision information to a Serializable object. The revision identifiers is used by
upcasters to decide whether they need to process a certain serialized event. Generally, the revision identifier
needs to be modified (increased) each time the structure of an event has been changed in an incompatible manner.
Although revision identifiers are inherited, you are strictly advised to only annotate the actual implementation
classes used. This will make it easier to keep the necessary upcasters up-to-date.