Carli/1988 giant file jigsaw error

[crocka]

Description

This pr fixes #1988. Associated backend PR is #1288. The pendingSynchronisedTiles map in the TileService failed to clean up itself with each render, causing messy tiles to be rendered during panning and zooming. Also, syncId and tileCount are added to the RasterSyncMessage because there was not any robust method to determine whether the required tiles in a sync group have been transmitted, causing missing tiles during animation. Lastly, the pr fixed the blinking of the vector overlay during animation due to racing condition that caused image rendering before all the vector overlay tiles have been transmitted.

Checklist

For linked issues (if there are):

• assignee and label added
• ZenHub issue connection, board status, and estimate updated

For the pull request:

• reviewers and assignee added
• ZenHub estimate, milestone, and release (if needed) added
• e2e test passing / corresponding fix added
• changelog updated / no changelog update needed
• protobuf updated to the latest dev commit / no protobuf update needed
• BackendService unchanged / BackendService changed and corresponding ICD test fix added

[kswang1029]

the solution with sync_id works nicely as far as I can tell. No missing tiles after animation stopping, or during animation playback. Vector overlay is rendered properly during/after animating as well. 👍 Thanks @crocka and @pford.

[YuHsuan-Hwang]

Nice work. 👍

[YuHsuan-Hwang]

Ready for merge. @crocka Please update the change log, thanks.
I wonder if this PR also fixes missing tile related issues #2026, #954, or #794?

[crocka]

I believe that it also resolved issue #2026, but further testing is required to confirm that. @YuHsuan-Hwang

[YuHsuan-Hwang]

Let's first close 1988 for now then.