feat(Async): StartTaskImmediate

[bartelink]

Addresses the task start+await aspect of fsharp/fslang-suggestions#1284

See also fsharp/fslang-suggestions#1467

Checklist

• Test cases added
• Update Await/AwaitTask xmldoc to mention that this is how you tie in cancellation
• self review
• Release notes entry updated
• Close Add Async.AwaitTask overloads which helps with CancellationToken passing, and a new warning fsharp/fslang-suggestions#1284 ?

[github-actions]

❗ Release notes required

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✅ Found changes and release notes in following paths:

Change path	Release notes path	Description
`src/FSharp.Core`	docs/release-notes/.FSharp.Core/11.0.100.md

[Copilot]

Pull request overview

This PR introduces Async.StartTaskImmediate, a new FSharp.Core API that runs a task factory with the ambient Async.CancellationToken and then awaits the produced task/task-like value using Async.Await (non-AggregateException wrapping) semantics. It also updates documentation and unit tests to cover the new behavior and updates the public-surface baselines and release notes accordingly.

Changes:

• Add Async.StartTaskImmediate overloads for Task, Task<'T>, ValueTask, ValueTask<'T>, plus an SRTP-based overload for task-like .GetAwaiter() values.
• Update Await/AwaitTask xmldoc to point users to StartTaskImmediate for the “start + await with cancellation” scenario.
• Add/extend unit tests and update surface area baselines + release notes.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
tests/FSharp.Core.UnitTests/FSharp.Core/Microsoft.FSharp.Control/AsyncType.fs	Adds coverage for StartTaskImmediate across Task/ValueTask and task-like awaitables.
tests/FSharp.Core.UnitTests/FSharp.Core.SurfaceArea.netstandard21.release.bsl	Updates netstandard2.1 release surface area baseline for the new APIs.
tests/FSharp.Core.UnitTests/FSharp.Core.SurfaceArea.netstandard21.debug.bsl	Updates netstandard2.1 debug surface area baseline for the new APIs.
tests/FSharp.Core.UnitTests/FSharp.Core.SurfaceArea.netstandard20.release.bsl	Updates netstandard2.0 release surface area baseline for the new Task-only APIs.
tests/FSharp.Core.UnitTests/FSharp.Core.SurfaceArea.netstandard20.debug.bsl	Updates netstandard2.0 debug surface area baseline for the new Task-only APIs.
src/FSharp.Core/async.fsi	Adds public API declarations and xmldoc for StartTaskImmediate, plus cross-references from Await/AwaitTask.
src/FSharp.Core/async.fs	Implements StartTaskImmediate in terms of binding Async.CancellationToken and awaiting via Async.Await.
docs/release-notes/.FSharp.Core/11.0.100.md	Adds a release note entry for Async.StartTaskImmediate.

Suppressed comments (1)

tests/FSharp.Core.UnitTests/FSharp.Core/Microsoft.FSharp.Control/AsyncType.fs:906

• This new test module should also be part of NotThreadSafeResourceCollection, otherwise it may run in parallel with tests that mutate the global default cancellation token (Async.CancelDefaultToken), causing nondeterministic failures.

module AsyncStartTaskImmediateTaskLikeTests =

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