Optimise channel list view updates

[laevandus]

🔗 Issue Link

PBE-5004

🎯 Goal

Reduce hitches and hangs while scrolling the channel list

🛠 Implementation

• Remove explicit view ids from channel list (causes full view reloads and not needed after ChatChannel equality implementation was changed)
• swipedChannelId sometimes causes unnecessary view updates while just scrolling down
• Optimise channel avatar loading by not triggering updates on the channel list level and instead observing it on the ChannelAvatarView level instead (more concise view update cycle when avatar loading finishes)

🧪 Testing

Exploratory testing on channel list updates (last message preview, sorting)

🎨 Changes

I did measurements using iPhone 12 Pro Max and repeated each measurement 3 times.
Steps:

1. Use "Animation Hitches" template
2. Launch the demo app and wait until it settles (account Chewbacca)
3. Slowly scroll down in the channel list until we reach the very last channel (paginating to the oldest channel)
   Count hitches and hangs during the duration of scrolling in the channel list.

Baseline

Measurement	Run 1	Run 2	Run 3
Hitches	18	22	24
Hangs	15	20	24

Remove explicit view ids

Measurement	Run 1	Run 2	Run 3
Hitches	18	16	13
Hangs	18	15	11

Remove explicit view ids + swipedChannelId change

Measurement	Run 1	Run 2	Run 3
Hitches	18	22	28
Hangs	16	10	12

Remove explicit view ids + swipedChannelId change + avatar optimisation

Measurement	Run 1	Run 2	Run 3
Hitches	7	5	5
Hangs	3	5	3

Based on the data the avatar change is the biggest contributor, while swipedChannelId does not add much or anything but I still decided to keep that tiny change.

In average the PR reduces hitches ~3.5 times and hangs ~5 times

☑️ Checklist

• I have signed the Stream CLA (required)
• Changelog is updated with client-facing changes
• New code is covered by unit tests
• Affected documentation updated (docusaurus, tutorial, CMS (task created)

[martinmitrevski]

seems like you forgot to push the OnLoadViewModifier?

[laevandus]

seems like you forgot to push the OnLoadViewModifier?

Indeed!

[Stream-SDK-Bot]

SDK Size

title	develop	branch	diff	status
StreamChatSwiftUI	6.96MB	7.01MB	0.05MB	🟢

[martinmitrevski]

great work, there are noticeable performance improvements 👏 I did some tests, things seem to be working well. @testableapple would be nice to also give it a go - mostly testing around the channel list. I would like to include this in the SwiftUI release today.

[laevandus]

QAd with @testableapple

[sonarqubecloud]

Quality Gate passed

Issues
89 New issues
0 Accepted issues

Measures
0 Security Hotspots
72.2% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud