[dotnet] Add SystemClock singleton

[RenderMichael]

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Add SystemClock singleton

Motivation and Context

This minimizes an allocation when using the WebDriverWait type, and adjacent types like components and waits

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• I have read the contributing document.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

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PR Type

Enhancement, Tests

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Description

• Introduced a singleton SystemClock.Instance to minimize allocations.

• Updated various classes to use SystemClock.Instance instead of creating new instances.

• Refactored FakeClock to HandCrankClock with improved naming and functionality.

• Adjusted related tests to align with the new SystemClock.Instance and HandCrankClock.

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Changes walkthrough 📝

	Relevant files
Enhancement	PopupWindowFinder.cs Use `SystemClock.Instance` in `PopupWindowFinder`                dotnet/src/support/UI/PopupWindowFinder.cs Replaced new SystemClock() with SystemClock.Instance. Simplified WebDriverWait initialization. +1/-1      SlowLoadableComponent{T}.cs Use `SystemClock.Instance` in `SlowLoadableComponent`        dotnet/src/support/UI/SlowLoadableComponent{T}.cs Replaced new SystemClock() with SystemClock.Instance. Updated constructor for consistency. +1/-1      DefaultWait{T}.cs Use `SystemClock.Instance` in `DefaultWait`                            dotnet/src/webdriver/Support/DefaultWait{T}.cs Replaced new SystemClock() with SystemClock.Instance. Simplified constructor logic. +1/-1      SystemClock.cs Introduce singleton instance for `SystemClock`                      dotnet/src/webdriver/Support/SystemClock.cs Added SystemClock.Instance as a singleton instance. Ensured thread-safe initialization. +5/-0      WebDriverWait.cs Use `SystemClock.Instance` in `WebDriverWait`                        dotnet/src/webdriver/Support/WebDriverWait.cs Replaced new SystemClock() with SystemClock.Instance. Updated constructor for consistency. +1/-1      HandCrankClock.cs Refactor `FakeClock` to `HandCrankClock`                                  dotnet/test/support/UI/HandCrankClock.cs Renamed FakeClock to HandCrankClock. Improved method naming for clarity. Simplified property and method implementations. +3/-12
Tests	SlowLoadableComponentTest.cs Update tests for `SystemClock` and `HandCrankClock`            dotnet/test/support/UI/SlowLoadableComponentTest.cs Updated tests to use SystemClock.Instance. Replaced FakeClock with HandCrankClock. Adjusted test logic to align with new clock implementation. +10/-14

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PR Reviewer Guide 🔍

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⏱️ Estimated effort to review: 2 🔵🔵⚪⚪⚪

🧪 PR contains tests

🔒 No security concerns identified

⚡ Recommended focus areas for review Thread Safety The SystemClock singleton instance is initialized using an auto-property. Consider using explicit thread-safe initialization pattern like lazy initialization to ensure thread safety. public static SystemClock Instance { get; } = new(); Naming Clarity The variable name 'fakeNow' could be renamed to something more descriptive like 'currentTime' or 'simulatedTime' to better reflect its purpose in the test clock implementation. private DateTime fakeNow = new DateTime(50000);

[qodo-merge-pro]

PR Code Suggestions ✨

Explore these optional code suggestions:

Category	Suggestion	Impact
General	Enforce singleton pattern implementation Add a private constructor to prevent direct instantiation of SystemClock since it's designed as a singleton. This enforces the singleton pattern and prevents potential multiple instances. dotnet/src/webdriver/Support/SystemClock.cs [29-34] public class SystemClock : IClock { /// <summary> /// An instance of the <see cref="SystemClock"/> type. /// </summary> public static SystemClock Instance { get; } = new(); + private SystemClock() { } + Apply this suggestion Suggestion importance[1-10]: 7 __ Why: Adding a private constructor is a good practice to properly implement the singleton pattern, preventing accidental instantiation and ensuring better encapsulation of the SystemClock class.	Medium

[RenderMichael]

SystemClock is a stateless type, and it gets referenced each time a WebDriverWait is created. This can remove an intermediate allocation from a commonly-used type.