[efficiency-improver] perf: defer GetTestName() to failure branches and avoid OfType<> alloc in AzureDevOpsReporter

src/Platform/Microsoft.Testing.Extensions.AzureDevOpsReport/AzureDevOpsReporter.cs

@@ -130,23 +130,24 @@ public async Task ConsumeAsync(IDataProducer dataProducer, IData value, Cancella
         EnsureEnabledConfigurationLoaded();
         TestNodeStateProperty? nodeState = nodeUpdateMessage.TestNode.Properties.SingleOrDefault<TestNodeStateProperty>();
         string testDisplayName = nodeUpdateMessage.TestNode.DisplayName;
-        string testName = GetTestName(nodeUpdateMessage.TestNode);
 
+        // Defer GetTestName() to failure branches only: for passing/skipped/in-progress tests
+        // nodeState falls through the switch with no match and testName is never needed.
         switch (nodeState)
         {
             case FailedTestNodeStateProperty failed:
-                await WriteExceptionAsync(testDisplayName, testName, failed.Explanation, failed.Exception, cancellationToken).ConfigureAwait(false);
+                await WriteExceptionAsync(testDisplayName, GetTestName(nodeUpdateMessage.TestNode), failed.Explanation, failed.Exception, cancellationToken).ConfigureAwait(false);
                 break;
             case ErrorTestNodeStateProperty error:
-                await WriteExceptionAsync(testDisplayName, testName, error.Explanation, error.Exception, cancellationToken).ConfigureAwait(false);
+                await WriteExceptionAsync(testDisplayName, GetTestName(nodeUpdateMessage.TestNode), error.Explanation, error.Exception, cancellationToken).ConfigureAwait(false);
                 break;
 #pragma warning disable CS0618, MTP0001 // Type or member is obsolete
             case CancelledTestNodeStateProperty cancelled:
 #pragma warning restore CS0618, MTP0001 // Type or member is obsolete
-                await WriteExceptionAsync(testDisplayName, testName, cancelled.Explanation, cancelled.Exception, cancellationToken).ConfigureAwait(false);
+                await WriteExceptionAsync(testDisplayName, GetTestName(nodeUpdateMessage.TestNode), cancelled.Explanation, cancelled.Exception, cancellationToken).ConfigureAwait(false);
                 break;
             case TimeoutTestNodeStateProperty timeout:
-                await WriteExceptionAsync(testDisplayName, testName, timeout.Explanation, timeout.Exception, cancellationToken).ConfigureAwait(false);
+                await WriteExceptionAsync(testDisplayName, GetTestName(nodeUpdateMessage.TestNode), timeout.Explanation, timeout.Exception, cancellationToken).ConfigureAwait(false);
                 break;
         }
     }

src/Platform/Microsoft.Testing.Extensions.AzureDevOpsReport/TestNodeIdentity.cs

@@ -15,8 +15,20 @@ internal static class TestNodeIdentity
     /// fully-qualified name property is unavailable.
     /// </summary>
     public static string GetTestName(TestNode testNode)
-        => testNode.Properties
-            .OfType<SerializableKeyValuePairStringProperty>()
-            .FirstOrDefault(static property => property.Key == FullyQualifiedNamePropertyKey)?.Value
-            ?? testNode.DisplayName;
+    {
+        // Walk the PropertyBag once with the zero-allocation struct enumerator and short-circuit
+        // on the first matching key, avoiding the LINQ iterator/boxed-enumerator allocations that
+        // OfType<T>().FirstOrDefault(...) would incur.
+        using PropertyBag.PropertyBagEnumerator enumerator = testNode.Properties.GetStructEnumerator();
+        while (enumerator.MoveNext())
+        {
+            if (enumerator.Current is SerializableKeyValuePairStringProperty kvp
+                && kvp.Key == FullyQualifiedNamePropertyKey)
+            {
+                return kvp.Value;
+            }
+        }
+
+        return testNode.DisplayName;
+    }
 }