perf(historian): group-commit batch append on the historization outbox

tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/Historian/ContinuousHistorizationRecorderTests.cs

@@ -733,6 +733,37 @@ public sealed class ContinuousHistorizationRecorderTests : TestKit
             return ValueTask.CompletedTask;
         }
 
+        public ValueTask AppendBatchAsync(IReadOnlyList<HistorizationOutboxEntry> entries, CancellationToken ct)
+        {
+            if (entries.Count == 0)
+            {
+                return ValueTask.CompletedTask;
+            }
+
+            if (_yieldOnAppend)
+            {
+                return AppendBatchYieldingAsync(entries);
+            }
+
+            foreach (HistorizationOutboxEntry entry in entries)
+            {
+                AppendCore(entry);
+            }
+
+            return ValueTask.CompletedTask;
+        }
+
+        private async ValueTask AppendBatchYieldingAsync(IReadOnlyList<HistorizationOutboxEntry> entries)
+        {
+            // Same pool-thread-completion requirement as AppendYieldingAsync below — a group commit
+            // fsyncs once for the batch, so the yield happens once, before the entries are recorded.
+            await Task.Delay(1).ConfigureAwait(false);
+            foreach (HistorizationOutboxEntry entry in entries)
+            {
+                AppendCore(entry);
+            }
+        }
+
         private async ValueTask AppendYieldingAsync(HistorizationOutboxEntry entry)
         {
             // Must complete on a POOL thread, carrying no synchronization context — that is what a real

tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/ServiceCollectionExtensionsTests.cs

@@ -245,6 +245,9 @@ public sealed class ServiceCollectionExtensionsTests
         public long DroppedCount => 0;
         /// <summary>No-op append.</summary>
         public ValueTask AppendAsync(HistorizationOutboxEntry entry, CancellationToken ct) => ValueTask.CompletedTask;
+        /// <summary>No-op batch append.</summary>
+        public ValueTask AppendBatchAsync(IReadOnlyList<HistorizationOutboxEntry> entries, CancellationToken ct)
+            => ValueTask.CompletedTask;
         /// <summary>Always returns an empty batch.</summary>
         public ValueTask<IReadOnlyList<HistorizationOutboxEntry>> PeekBatchAsync(int max, CancellationToken ct)
             => ValueTask.FromResult<IReadOnlyList<HistorizationOutboxEntry>>(Array.Empty<HistorizationOutboxEntry>());