feat: add ToAsyncEnumerable

Author: woutervanranst

src/WouterVanRanst.Utils/Extensions/IEnumerableExtensions.cs

@@ -1,4 +1,6 @@
-namespace WouterVanRanst.Utils.Extensions;
+using System.Runtime.CompilerServices;
+
+namespace WouterVanRanst.Utils.Extensions;
 
 public static class IEnumerableExtensions
 {
@@ -72,4 +74,16 @@ public static IEnumerable<T> DuplicatesBy<T, TKey>(this IEnumerable<T> collectio
             .Where(group => group.Count() > 1)
             .SelectMany(group => group);
     }
+
+    public static async IAsyncEnumerable<T> ToAsyncEnumerable<T>(this IEnumerable<T> source, [EnumeratorCancellation] CancellationToken cancellationToken = default)
+    {
+        foreach (var item in source)
+        {
+            cancellationToken.ThrowIfCancellationRequested();
+            yield return item;
+
+            // Give the scheduler a chance to run other work; keeps it truly async-friendly.
+            await Task.Yield();
+        }
+    }
 }