feat: add OnTriggeredOrReplay method to replay watcher-triggered notifications

[vbreuss]

This pull request introduces a new WatcherChangeDescription class to provide richer context for watcher-triggered file system notifications, and updates the watcher notification APIs to use this new type. It also adds support for replaying watcher-triggered notifications to newly registered callbacks, similar to the existing notification replay mechanism. The changes ensure that consumers can filter or replay notifications by watcher instance and that notification history can be enabled or disabled for both standard and watcher-triggered events.

Watcher notification enhancements:

• Introduced the WatcherChangeDescription class, which extends ChangeDescription and includes a reference to the emitting IFileSystemWatcher, allowing consumers to filter notifications by watcher instance.
• Updated the IWatcherTriggeredHandler interface and related APIs to use WatcherChangeDescription instead of ChangeDescription, and added a new OnTriggeredOrReplay method to allow callbacks to receive both past and future watcher-triggered notifications.
• Implemented notification history and replay support for watcher-triggered notifications in ChangeHandler, including thread-safety improvements and opt-out support.

Notification history configuration:

• Updated MockFileSystemOptions and related documentation to clarify that notification history now applies to both standard and watcher-triggered streams, and that disabling history affects both.

Internal improvements:

• Added a copy constructor to ChangeDescription to support the new WatcherChangeDescription type.
• Updated FileSystemWatcherMock to use the new watcher-triggered notification API.

[Copilot]

Pull request overview

Adds watcher-specific change descriptions and replay support for watcher-triggered notifications in the mock file system notification pipeline.

Changes:

• Introduces WatcherChangeDescription with the emitting watcher instance.
• Adds watcher-triggered replay/history handling in ChangeHandler.
• Updates tests and API baselines for the new watcher notification API.

Reviewed changes

Copilot reviewed 13 out of 13 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
Source/Testably.Abstractions.Testing/FileSystem/WatcherChangeDescription.cs	Adds watcher-aware change description type.
Source/Testably.Abstractions.Testing/FileSystem/IWatcherTriggeredHandler.cs	Updates watcher notification API and adds replay method.
Source/Testably.Abstractions.Testing/FileSystem/ChangeHandler.cs	Implements watcher-triggered history and replay.
Source/Testably.Abstractions.Testing/FileSystem/FileSystemWatcherMock.cs	Passes emitting watcher into watcher-triggered notifications.
Source/Testably.Abstractions.Testing/FileSystem/ChangeDescription.cs	Adds copy constructor for watcher descriptions.
Source/Testably.Abstractions.Testing/MockFileSystem.cs	Updates option documentation for watcher history.
Tests/Testably.Abstractions.Testing.Tests/FileSystem/ChangeHandlerTests.cs	Adds watcher replay tests and updates callback types.
Tests/Api/Testably.Abstractions.Api.Tests/Expected/Testably.Abstractions.Testing_netstandard2.0.txt	Updates API baseline.
Tests/Api/Testably.Abstractions.Api.Tests/Expected/Testably.Abstractions.Testing_netstandard2.1.txt	Updates API baseline.
Tests/Api/Testably.Abstractions.Api.Tests/Expected/Testably.Abstractions.Testing_net6.0.txt	Updates API baseline.
Tests/Api/Testably.Abstractions.Api.Tests/Expected/Testably.Abstractions.Testing_net8.0.txt	Updates API baseline.
Tests/Api/Testably.Abstractions.Api.Tests/Expected/Testably.Abstractions.Testing_net9.0.txt	Updates API baseline.
Tests/Api/Testably.Abstractions.Api.Tests/Expected/Testably.Abstractions.Testing_net10.0.txt	Updates API baseline.

Comments suppressed due to low confidence (1)

Source/Testably.Abstractions.Testing/FileSystem/IWatcherTriggeredHandler.cs:45

• Adding OnTriggeredOrReplay directly to the public interface is also a breaking change for any external implementations of IWatcherTriggeredHandler, because they must now implement the new member. Consider adding this as an extension method backed by an internal capability, or introducing a separate derived interface, so existing implementers remain compatible.

	IAwaitableCallback<WatcherChangeDescription> OnTriggeredOrReplay(
		Action<WatcherChangeDescription>? triggerCallback = null,
		Func<WatcherChangeDescription, bool>? predicate = null);

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
89.5% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[github-actions]

This is addressed in release v6.4.0.