- use a separate enum for the states - chunks have different transitions than instances.
- use transactional update events for work-chunk state transitions
- introduce spec-test to define behaviour of batch2 storage
- replace synchronized facade with simpler ProxyUtil handler.
- change job cancellation to db update query

Change work-chunk creation to be first event in state machine.

* Use java event names for work chunk transitions.

* Cherry-pick d5ebd1f from rel_6_4

Avoid fetching work-chunk data (#4622)

* add end time to reduction step (#4640)

* add end time to reduction step

* add changelog

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Co-authored-by: Long Ma <[email protected]>
(cherry picked from commit 37f5e59)

* Cancel processing

Provide error message in cancelled jobs, and avoid transitions in final states.

* Apply tx boundary to starting job and first chunk.

* cleanup

* Apply tx boundary to work chunk processing

* Delete BatchWorkChunk

* Introduce events for job create, and chunk dequeue

* Apply tx boundary to chunk handler

* Move instance cancellation to database

* tx boundary around stats collection and completion

* tx boundary around stats collection and completion

* Extend tx boundary to error, fail, and cancel

* Move failure into status calc

* ERROR is not an "ended" state.

* Revert generics cleanup to avoid noise

* Avoid sending gated chunks twice.

* Make no-data path safer.  Cleanup

* Fix mock test for step advance.

* Delete unsafe updateInstace() call

* Cleanup

* Changelog and notes

* Fix cancel boundary.  Cleanups

* Cleanup

* Sort mongo chunks for stable paging.

Other cleanup

* Document error handling

* Cleanup

* Update hapi-fhir-jpaserver-test-utilities/src/main/java/ca/uhn/fhir/jpa/test/Batch2JobHelper.java

Co-authored-by: StevenXLi <[email protected]>

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Co-authored-by: longma1 <[email protected]>
Co-authored-by: StevenXLi <[email protected]>

* Fix intermittent in batch2 tests

* Add changelog

* Test fix

* Resolve intermittent

* Reducer changes

* Test fix

* Test fixes

* Resolve fixme

* Fix changelog

* Full implementation, test, changelogs

* Add changelogs

* Add default method

* Update hapi-fhir-storage-batch2-jobs/src/main/java/ca/uhn/fhir/batch2/jobs/export/WriteBinaryStep.java

Co-authored-by: James Agnew <[email protected]>

* Code Review Comments

* Compilation failures

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Co-authored-by: James Agnew <[email protected]>