Use structs for element factory

[twsouthwick]

This helps a bit with performance:

Before

Method	Mean	Error	StdDev	Gen0	Gen1	Allocated
Create	41.71 us	0.776 us	0.762 us	6.1035	0.2441	51.52 KB
CreateNoSave	40.32 us	0.729 us	0.780 us	6.1035	0.2441	51.52 KB
ReadFile	847.70 us	16.828 us	29.474 us	29.2969	3.9063	255.22 KB

After

Method	Mean	Error	StdDev	Gen0	Gen1	Allocated
Create	40.80 us	0.665 us	0.589 us	6.1035	0.2441	51.52 KB
CreateNoSave	40.50 us	0.561 us	0.438 us	6.1035	0.2441	51.52 KB
ReadFile	830.07 us	14.996 us	22.446 us	29.2969	3.9063	255.22 KB

[azure-pipelines]

There was an error handling pipeline event 018f3cc4-a623-46cc-878d-73bfd5be29a3.

[Copilot]

Pull Request Overview

This PR refactors the element factory implementation to use structs and file-scoped namespaces for a slight performance boost.

• Converted ElementFactory from a class to a readonly struct and removed the generic Create() method.
• Updated ElementFactoryCollection to use a List instead of an array and applied file-scoped namespaces.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
src/DocumentFormat.OpenXml.Framework/Framework/Metadata/ElementFactoryCollection.cs	Replaced array with List, updated sorting and binary search, and switched to a file-scoped namespace.
src/DocumentFormat.OpenXml.Framework/Framework/Metadata/ElementFactory.cs	Changed from a sealed class to a readonly struct and removed the generic Create() factory method.

Comments suppressed due to low confidence (1)

src/DocumentFormat.OpenXml.Framework/Framework/Metadata/ElementFactoryCollection.cs:18

• Changing the constructor parameter from IEnumerable to List restricts the accepted input type; ensure that all call sites are updated to pass a List to prevent potential runtime issues.

public ElementFactoryCollection(List<ElementFactory> lookup)

[Copilot]

Changing ElementFactory from a class to a struct introduces value semantics that can lead to unintended copying; please verify that all consumers handle these semantics correctly and that removing the generic Create() method is intentional.

Suggested change

	internal readonly struct ElementFactory(OpenXmlSchemaType type, Func<OpenXmlElement> factory)
	{
	internal class ElementFactory
	{
	private readonly OpenXmlSchemaType type;
	private readonly Func<OpenXmlElement> factory;
	public ElementFactory(OpenXmlSchemaType type, Func<OpenXmlElement> factory)
	{
	this.type = type;
	this.factory = factory;
	}

[github-actions]

Test Results

0 files   -     56  0 suites   - 56   0s ⏱️ - 57m 13s
0 tests  -  2 050  0 ✅  -  2 047  0 💤  -  3  0 ❌ ±0 
0 runs   - 31 992  0 ✅  - 31 956  0 💤  - 36  0 ❌ ±0 

Results for commit 336ee59. ± Comparison against base commit b127a66.

♻️ This comment has been updated with latest results.