[AIT-280] feat: Implement apply-on-ACK (RTO20) prototype

[lawrence-forooghian]

Implement the apply-on-ACK feature which applies LiveObjects operations
locally upon receipt of an ACK message, rather than waiting for the
operation echo. This reduces perceived latency for users.

Key changes:

• Add appliedOnAckSerials set and bufferedAcks array to MutableState
• Add PublishResult type containing serials array from ACK res[i].serials
• Implement RTO9a3: Skip OBJECT messages already applied on ACK
• Implement RTO5c9-11: Clear/process buffered ACKs on sync completion
• Add publishAndApply() method for the main apply-on-ACK flow
• Add canApplyOperationForAck/applyForAck helpers to LiveMap/LiveCounter
• Integrate apply-on-ACK into set/remove/increment/decrement operations

PublishResult.serials is an array where each element corresponds 1:1 to
the ObjectMessages that were published. publishAndApply processes each
message with its corresponding serial at the matching index.

Note: Full functionality requires ably-cocoa changes:

• CD2j: Add siteCode to ConnectionDetails
• Update nosync_sendObject callback to include serials from ACK

Co-Authored-By: Claude Opus 4.5 noreply@anthropic.com

[coderabbitai]

Important

Review skipped

Draft detected.

Please check the settings in the CodeRabbit UI or the .coderabbit.yaml file in this repository. To trigger a single review, invoke the @coderabbitai review command.

You can disable this status message by setting the reviews.review_status to false in the CodeRabbit configuration file.

✨ Finishing touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch AIT-280-prototype-apply-on-ack

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands and usage tips.}