Give your simulator superpowers

RocketSim: An Essential Developer Tool
as recommended by Apple

Issue 275
Jun 12, 2025

This week's SwiftLee Weekly covers:

  • Notable WWDC changes
  • Automatic observation tracking for UIKit
  • What is it like to visit WWDC?

Enjoy this week's SwiftLee Weekly!

THIS WEEK'S BLOG POST

@concurrent explained with code examples

One of my favorite announcements of this week is all the concurrency changes. One of the new attributes you'll need in Swift 6.2 is the @concurrent attribute, which I'll explain in this week's article.

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CURATED FROM THE COMMUNITY

Crafting Liquid Glass app icons with Icon Composer

It’s time to update your app icons and luckily enough, we have the Icon Composer to help us out!
createwithswift.com

Automatic Observation Tracking in UIKit and AppKit: The Feature Apple Forgot to Mention | Peter Steinberger

I love those hidden changes that you don’t immediately see in one of the WWDC sessions. This one seems to be a big one for those using UIKit!
steipete.me

A (Re-)Introduction to ExtensionKit

I recall the first time I looked at ExtensionKit, hoping for more than it actually delivered. I’ll definitely revisit the new changes this year, especially XPCSession.
massicotte.org

Developer experience wins from WWDC25

A new macro, testing improvements, a new open-source CLI. There’s a lot for developer experience and this article gives a great overview.
tuist.dev

Introducing PickerKit for SwiftUI

Many of you know that I’m working on Simulator Camera support, and this new SwiftUI package means I’ll have a bit more work to do!
danielsaidi.com

SWIFT EVOLUTION

An overview of last week's Swift Proposal state changes. Check them out when they're in review, as it's your opportunity to influence the direction of Swift's future.

No changes, but hey, we got WWDC!

QUESTION OF THE WEEK

What is it like to visit WWDC?

You might notice that this is a bit of an odd newsletter edition. I'm writing this issue on a Thursday after a whole week of WWDC events. It's a fantastic event, full of meetings, events, and announcements.

My first WWDC was in 2013, and I recall watching at least 15 sessions by Thursday. Now, I barely find the time to write this newsletter since there are so many events to attend!

Many companies organize parties, and there are community-driven events like CommunityKit where I even got to host a RocketSim meetup (with a fun paperplane challenge). But aside from that, it's been an opportunity to meet with many Apple engineers and relationships.

Getting to WWDC in person, even without a ticket, can make a huge impact on your inspiration and motivation. You'll be able to create new relationships, contacts that might turn into opportunities years later.

I attended WWDC in 2023 as well and met an engineer who worked at Meta. Now, two years later, I got invited to present my developer tool RocketSim in front of the app developers of Meta, since it's their go-to developer tool for recordings & design comparisons.

Now, it's time to rewind and get back home. I'll be going through all the changes in the upcoming week, writing new articles, and updating my Swift Concurrency Course. I hope you've had a fantastic WWDC week, whether you were here or in person watching many of the sessions. Stay tuned for new SwiftLee articles soon!

Want to have your question answered next week? Ask your question via this form (anonymously) or reply to this email with your question.

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Thank you so much for your support, and until next Tuesday,

Antoine