Annotation Type Prepare
When a SRA is asked to commit any bean resource classes that were invoked in its context will
be notified by calling methods marked with the @Prepare annotation. If a resource class contains
multiple Prepare annotations an arbitrary one is chosen.
If the participant prepares successfully it must return a 200 code. If it cannot then it must return
a 409 code. Any response other than 200 MUST cause the SRA to roll back.