fix: Remove virtual GetEventChannel from FeatureProvider

[askpt]

This PR

This pull request includes changes to the EventChannel handling in the OpenFeature library to improve code consistency and reliability.

Improvements to EventChannel handling:

• src/OpenFeature/EventExecutor.cs: Removed unnecessary null-conditional operator when completing the Writer of the event channel.
• src/OpenFeature/FeatureProvider.cs: Made the GetEventChannel method non-virtual to ensure consistent behavior across different implementations.

Related Issues

Related to #358

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 85.71%. Comparing base (46274a2) to head (8a016f3).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #401      +/-   ##
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- Coverage   85.90%   85.71%   -0.19%     
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  Files          39       39              
  Lines        1603     1603              
  Branches      172      171       -1     
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- Hits         1377     1374       -3     
- Misses        189      191       +2     
- Partials       37       38       +1     

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[Copilot]

Pull Request Overview

This PR improves event channel handling in the OpenFeature library by ensuring proper shutdown of unused providers and updating test setups for channel operations.

• Corrects event channel completion logic by removing an unnecessary null-conditional operator.
• Updates the event channel API in FeatureProvider by removing the virtual modifier.
• Enhances test setup by adding necessary imports to support channel operations.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
src/OpenFeature/EventExecutor.cs	Removes the null-conditional operator when completing the event channel writer to ensure proper shutdown of unused providers.
src/OpenFeature/FeatureProvider.cs	Removes the virtual modifier on GetEventChannel, potentially affecting subclass overrides.

Comments suppressed due to low confidence (2)

src/OpenFeature/EventExecutor.cs:150

• Removing the null-conditional operator requires that GetEventChannel() is guaranteed to return a non-null channel. Please double-check that no null value is possible to avoid a potential NullReferenceException.

oldProvider.GetEventChannel().Writer.Complete();

src/OpenFeature/FeatureProvider.cs:143

• Removing the virtual keyword on GetEventChannel() may affect subclass implementations that override this behavior. Verify that this change is intentional and that no subclass relies on overriding this method.

public Channel<object> GetEventChannel() => this.EventChannel;