Add ResizableSemaphore

[Copilot]

Ports ResizableSemaphore from YoutubeDownloader into PowerKit — a semaphore whose max concurrency count can be adjusted at runtime.

Implementation

• PowerKit/ResizableSemaphore.cs

  • #if NET40_OR_GREATER || NETSTANDARD || NET file guard
  • Lock + EnterScope() (PolyShim) instead of object + lock
  • Refresh() acquires _lock itself; all callers release the lock before calling Refresh(), avoiding re-entrancy issues with .NET 9's non-reentrant System.Threading.Lock
  • _maxCount backing field inlined using C# 13 field keyword; getter is lock-free (get => field) so Refresh() can read MaxCount without re-entering the lock
  • AcquiredAccess file class replaced with Disposable.Create(Release) — no separate type needed
  • await using on CancellationTokenRegistration replaced with using var — IAsyncDisposable on that type is .NET 6+ only
  • ConfigureAwait(false) on the awaited task
  • Two partial class declarations merged into one

• PowerKit.Tests/ResizableSemaphoreTests.cs — 4 consolidated tests covering blocking at limit, cancellation, MaxCount changes unblocking waiters, and disposal behaviour

Usage

using var semaphore = new ResizableSemaphore { MaxCount = 3 };

// Blocks if 3 accesses are already active
using var access = await semaphore.AcquireAsync(cancellationToken);
// ... do work ...
// access released on dispose

[Copilot]

Pull request overview

Adds a ResizableSemaphore concurrency primitive to PowerKit, allowing the maximum concurrency level to be adjusted at runtime.

Changes:

• Introduces ResizableSemaphore with async acquire/release semantics and dynamic MaxCount updates.
• Adds unit tests covering acquisition limits, blocking behavior, cancellation, disposal behavior, and unblocking via MaxCount changes.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
PowerKit/ResizableSemaphore.cs	Implements the resizable semaphore and its disposable access handle.
PowerKit.Tests/ResizableSemaphoreTests.cs	Adds behavioral tests for acquire/release, cancellation, disposal, and resizing.

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[Tyrrrz]

@copilot ResizableSemaphoreAccess can be replaced with Disposable.Create

[codecov]

Codecov Report

❌ Patch coverage is 96.49123% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 93.99%. Comparing base (35b770e) to head (da409cf).
⚠️ Report is 2 commits behind head on prime.

Files with missing lines	Patch %	Lines
PowerKit/ResizableSemaphore.cs	94.87%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##            prime      #71      +/-   ##
==========================================
+ Coverage   93.93%   93.99%   +0.06%     
==========================================
  Files         130      132       +2     
  Lines        2557     2616      +59     
  Branches      202      205       +3     
==========================================
+ Hits         2402     2459      +57     
- Misses        112      113       +1     
- Partials       43       44       +1     

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[Copilot]

@copilot ResizableSemaphoreAccess can be replaced with Disposable.Create

ResizableSemaphoreAccess was already replaced with Disposable.Create(Release) in a previous commit (abfff4b). No ResizableSemaphoreAccess type remains in the code.

[Tyrrrz]

@copilot fix formatting please

[Copilot]

@copilot fix formatting please

Fixed in 1a5d6a5. CSharpier collapsed the multiline cancellationToken.Register(...) call to a single line, and restored the null-forgiving ! on waiter!.TrySetResult() (needed for netstandard2.0). Build now passes cleanly.