Swift Concurrency adoption guidelines for Swift Server Libraries

[fabianfett]

This is a first draft for "Swift Concurrency adoption guidelines for Swift Server Libraries" that was written by @ktoso and me. Looking forward to your input.

[ktoso]

Some follow ups we want to do:

• [ ] common pitfalls
  • [ ] the ordering issues with Task{} Task{} and sending messages to an actor from those (there's no ordering guarantee); I explain the issue here: https://forums.swift.org/t/task-is-order-of-task-execution-deterministic/51553/2
• [ ] similar guide for application developers; "wait for X to release" etc;
• [ ] some practical example for simple functions, perhaps link to https://github.com/grpc/grpc-swift/releases/tag/1.4.1-async-await.1 diff which shows the "side by side" adding
• [ ] example with async sequence

[ktoso]

Thanks David!

[ktoso]

Thanks a lot for the edits @kmahar !

[adam-fowler]

• [ ] example with async sequence

Soto has an AsyncSequence sample used for paginated results. It is full of generics so might not be the simplest example though. https://github.com/soto-project/soto-core/blob/async-await/Sources/SotoCore/AWSClient%2BPaginate%2Basync.swift

[ktoso]

Going through including feedback last time and will merge, thanks for all the comments!

[ktoso]

Ok i think i applied all changes. Please do feel free to send in PRs and keep this guide growing with more patterns and ideas!

[ktoso]

Meh can't edit this PR branch, so will merge and PR followups