Strengthen data-race safety guarantees

[timonkrebs]

Swift claims to achieve data race savety with structured concurrency and actors. Adding actors to MemoizR would lead to similar benefits.

https://github.com/apple/swift-evolution/blob/main/proposals/0412-strict-concurrency-for-global-variables.md

https://github.com/apple/swift-evolution/blob/main/proposals/0423-dynamic-actor-isolation.md

https://github.com/apple/swift-evolution/blob/main/proposals/0392-custom-actor-executors.md

https://swift.org/blog/sswg-update-2023/

A key focus of language development for Swift 6 is improving the usability of strict concurrency checking by mitigating false positive concurrency errors in common patterns proven to be safe, Borla said. Structured concurrency has been cited as a server-side goal for the Swift language.

https://www.infoworld.com/article/3714341/swift-achieves-data-race-safety.html