Check for ICollection<T>in GetEnumerator()

[Erarndt]

Fixes #

Context

There is a meaningful amount of allocations coming from resizing a List<T> in CopyOnReadEnumerable.GetEnumerator()

Total allocations in this path are ~68MB for OrchardCore. We won't eliminate them entirely, but this will reduce them.

Changes Made

Testing

Notes

[Copilot]

Pull Request Overview

This PR optimizes the CopyOnReadEnumerable.GetEnumerator() method by checking for ICollection<T> to get the collection count before initializing a List<T>. This reduces memory allocations by avoiding list resizing during enumeration.

• Adds ICollection<T> check to obtain count before IReadOnlyCollection<T> check
• Uses collection count for initial List<T> capacity to prevent dynamic resizing
• Targets ~68MB allocation reduction in OrchardCore scenarios

[Copilot]

The ICollection<T> check should be placed before the IReadOnlyCollection<T> check since ICollection<T> is more specific and commonly implemented. Consider reordering these conditions to check ICollection<T> first for better performance in common scenarios.