Mark Operator Closures as @Sendable

[AndreiArdelean1]

Mark Operator Closures as @sendable to Prevent Crashes in Swift 6 Isolated Contexts #2638

In Swift 6, closures created in an isolated context automatically inherit the isolation of that context, unless they are marked as @sendable. Because of this, creating an operation like map, flatMap, distinctUntilChanged, etc. from an isolated context, but calling it from a different thread, causes the call to crash.

[AndreiArdelean1]

Added PR #2610 here

[AndreiArdelean1]

@freak4pc Hi! Just checking in to see if there’s any chance this PR could be reviewed. Getting this merged is essential for updating my project to Swift 6, and I imagine others may be in a similar situation. I’m eager to get feedback or make any adjustments needed to move it forward. Thanks so much for your time!

[freak4pc]

Hey @AndreiArdelean1 -
It's a very large change. Something that could speed up the mergeability of it is to reduce risk -
If you are willing to cut a release of your own app that targets this branch and confirm there are no production-related issues (crashes, misbehaviors) it would make it much simpler, since it will then only be a code review, and not a functionality review which would be very problematic to do without real-world tests on this.