firebase-ios-sdk

GDT: Retry uploading batches failed to upload before the app termination (#5942)

* GDTCCTUploaderTest: test a lost batch upload retry

* GDTCCTUploader: refactoring to prepare for lost batches uploading

* GDTCCTUploader: Upload previously batched events first

* Fix GDTCCTTestStorage

* Refactor GDTCCTUploaderTest

* GDTCORFlatFileStorageTest: batch tests

* GDTCORFlatFileStorage: refactor removeBatchWithID to prepare for eventsForbatchID

* eventsInBatchWithID implementation

* Fix tests

* Uploader fix for empty batch state

* GDTCORUploadCoordinator: high priority targets

* style

* GDTCCTUploaderTest

* GDTCCTUploaderTest: cleanup

* Cleanup and API docs.

* GDTCORUploadCoordinator: revert high priority targets

* GDTCCTUploader: make sure GDTCOREventQoSFast is part of a regular batch as well.

* Cleanup

* GDTCCTUploader: don't report ready for upload until there are events.

* GDTCCTUploaderTest: move failed batch back to the queue

* GDTCORFlatFileStorage: removeBatchWithID with deleteEvents==NO

* GDTCORFlatFileStorage: remove batch directory

* style

* GDTCORFlatFileStorage: comments and debug logs

* formatting

* GDTCCTUploaderTest: recover tests

* GDTCCTTestServer: support for async request handler

* GDTCCTUploaderTest: ongoing request tests

* GDTCORStorageProtocol: remove redundant `eventsInBatchWithID` method.

* GDTCORFlatFileStorageTest: `removeBatchWithID` tests

* Cleanup

* GDTCORFlatFileStorage: cleanup

* GDTCORFlatFileStorageTest: better coverage and cleanup

* Comments and improvements

* GDTCCTUploaderTest: reduce code duplication

* GDTCCTUploaderTest: conditions tests

* GDTCCTUploader: fix next request wait time

* run ./scripts/style.sh