✨ [RUM-6581] Add an init parameter to chose feature flags event collection

[RomanGaignault]

Motivation

For now, feature flags are only included in views and errors. This was chosen to limit the feature flags impact on bandwidth, but now that we implemented compression, we could re-evaluate.

Changes

Instead of enabling feature flag collections on all events at once, we could provide an init parameter to allow customers to chose on which events they want to collect feature flags:
init({
collectFeatureFlagsOn: ['long_task', 'error', 'vital']
})

Testing

• Local
• Staging
• Unit
• End to end

---

I have gone over the contributing documentation.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 96.96970% with 1 line in your changes missing coverage. Please review.

Project coverage is 93.68%. Comparing base (1a38806) to head (54e65ab).

Files with missing lines	Patch %	Lines
packages/rum-core/src/boot/startRum.ts	66.66%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3283      +/-   ##
==========================================
+ Coverage   93.67%   93.68%   +0.01%     
==========================================
  Files         288      289       +1     
  Lines        7600     7618      +18     
  Branches     1730     1735       +5     
==========================================
+ Hits         7119     7137      +18     
  Misses        481      481              

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[cit-pr-commenter]

Bundles Sizes Evolution

📦 Bundle Name	Base Size	Local Size	𝚫	𝚫%	Status
Rum	144.58 KiB	145.50 KiB	937 B	+0.63%	✅
Logs	51.09 KiB	51.09 KiB	0 B	0.00%	✅
Rum Slim	103.42 KiB	104.32 KiB	917 B	+0.87%	✅
Worker	24.50 KiB	24.50 KiB	0 B	0.00%	✅

🚀 CPU Performance

Action Name	Base Average Cpu Time (ms)	Local Average Cpu Time (ms)	𝚫
addglobalcontext	0.003	0.002	-0.000
addaction	0.042	0.053	0.011
addtiming	0.001	0.001	0.000
adderror	0.050	0.095	0.044
startstopsessionreplayrecording	0.010	0.013	0.003
startview	0.463	0.490	0.027
logmessage	0.031	0.032	0.001

🧠 Memory Performance

Action Name	Base Consumption Memory (bytes)	Local Consumption Memory (bytes)	𝚫 (bytes)
addglobalcontext	27.68 KiB	28.57 KiB	911 B
addaction	56.92 KiB	59.05 KiB	2.13 KiB
addtiming	26.42 KiB	27.46 KiB	1.04 KiB
adderror	60.65 KiB	61.36 KiB	729 B
startstopsessionreplayrecording	25.01 KiB	26.71 KiB	1.71 KiB
startview	411.17 KiB	416.25 KiB	5.08 KiB
logmessage	60.54 KiB	61.16 KiB	627 B

🔗 RealWorld

[BenoitZugmeyer]

💬 suggestion: refactor your PR by ‏moving this in assembly.ts

[amortemousque]

@RomanGaignault, just for context, the assembly is where we set attributes that apply on multiple event types.
For instance:

• If an attribute applies on only on resources => resourceCollection.ts
• If an attribute applies on resource, error etc. => assembly.ts

[amortemousque]

You can probably look at what we do here

[RomanGaignault]

Great, I will update that ! Thanks for context 👍