[BeltranBulbarellaDD]

Motivation

Alternative to #5227 for RUM-19516: resource events wait in an idle-callback task queue (up to 1s) and are dropped when the page exits, so resources that finish right before the user leaves are never sent.

#5227 drains the queue on PREPARE_URGENT_FLUSH and relies on resource collection starting before view collection in startRum, so the final view update counts the drained resources. This PR makes that order explicit instead, with two page exit phases.

Changes

• New COLLECT_PENDING_EVENTS lifecycle event, notified right before PREPARE_URGENT_FLUSH (batch and event bridge paths):
  1. COLLECT_PENDING_EVENTS: collections emit what they are still processing. Resource collection flushes its task queue.
  2. PREPARE_URGENT_FLUSH: collections finalize their events (views, click actions…), which include what phase 1 collected.
• TaskQueue.flush(): runs pending tasks synchronously, each through callMonitored so a failing task doesn't prevent the batch from being sent.
• Discard resources with a non-finite duration (when performance is replaced, e.g. Playwright's page.clock.install()).

Same behavior as #5227, without depending on the order collections are started in. COLLECT_PENDING_EVENTS is also where takeRecords() or the replay mutation flush could go later.

Test instructions

yarn test:unit: startRum.spec.ts checks that the view and click action resource.count include the resources collected on unload. See #5227 for the e2e reproduction.

Checklist

• Tested locally
• Tested on staging
• Added unit tests for this change.
• Added e2e/integration tests for this change.
• Updated documentation and/or relevant AGENTS.md file

🤖 Generated with Claude Code

[cit-pr-commenter-54b7da]

Bundles Sizes Evolution

📦 Bundle Name	Base Size	Local Size	𝚫	𝚫%	Status
Rum Salesforce	191.13 KiB	191.27 KiB	+144 B	+0.07%	✅
Rum	191.11 KiB	191.25 KiB	+144 B	+0.07%	✅
Rum Salesforce Profiler	8.35 KiB	8.35 KiB	0 B	0.00%	✅
Rum Profiler	8.35 KiB	8.35 KiB	0 B	0.00%	✅
Rum Salesforce Recorder	32.04 KiB	32.04 KiB	0 B	0.00%	✅
Rum Recorder	32.04 KiB	32.04 KiB	0 B	0.00%	✅
Logs	60.10 KiB	60.10 KiB	0 B	0.00%	✅
Rum Slim	147.27 KiB	147.40 KiB	+139 B	+0.09%	✅
Worker	24.23 KiB	24.23 KiB	0 B	0.00%	✅
Rum Shopify	221.56 KiB	221.70 KiB	+144 B	+0.06%	✅
Rum Shopify Profiler	8.35 KiB	8.35 KiB	0 B	0.00%	✅
Rum Shopify Recorder	4.85 KiB	4.85 KiB	0 B	0.00%	✅

[datadog-prod-us1-3]

 

🎉 All green!

🧪 All tests passed
❄️ No new flaky tests detected

🎯 Code Coverage (details)
• Patch Coverage: 91.67%
• Overall Coverage: 77.30% (-0.01%)

_{This comment will be updated automatically if new data arrives.
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