diff --git a/src/Microsoft.Blazor/RenderTree/ArrayBuilder.cs b/src/Microsoft.Blazor/RenderTree/ArrayBuilder.cs
index b07445d878..d46bb5648d 100644
--- a/src/Microsoft.Blazor/RenderTree/ArrayBuilder.cs
+++ b/src/Microsoft.Blazor/RenderTree/ArrayBuilder.cs
@@ -45,8 +45,8 @@ namespace Microsoft.Blazor.RenderTree
         /// Appends a new item, automatically resizing the underlying array if necessary.
         /// </summary>
         /// <param name="item">The item to append.</param>
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public void Append(T item)
+        [MethodImpl(MethodImplOptions.AggressiveInlining)] // Just like System.Collections.Generic.List<T>
+        public void Append(in T item)
         {
             if (_itemsInUse == _items.Length)
             {
diff --git a/src/Microsoft.Blazor/RenderTree/RenderTreeBuilder.cs b/src/Microsoft.Blazor/RenderTree/RenderTreeBuilder.cs
index 22327e818d..e823fae230 100644
--- a/src/Microsoft.Blazor/RenderTree/RenderTreeBuilder.cs
+++ b/src/Microsoft.Blazor/RenderTree/RenderTreeBuilder.cs
@@ -159,7 +159,7 @@ namespace Microsoft.Blazor.RenderTree
         public ArrayRange<RenderTreeNode> GetNodes() =>
             _entries.ToRange();
 
-        private void Append(RenderTreeNode node)
+        private void Append(in RenderTreeNode node)
         {
             _entries.Append(node);
 
diff --git a/src/Microsoft.Blazor/RenderTree/RenderTreeDiffComputer.cs b/src/Microsoft.Blazor/RenderTree/RenderTreeDiffComputer.cs
index 0ea51a3f37..2a3694d1ea 100644
--- a/src/Microsoft.Blazor/RenderTree/RenderTreeDiffComputer.cs
+++ b/src/Microsoft.Blazor/RenderTree/RenderTreeDiffComputer.cs
@@ -286,7 +286,7 @@ namespace Microsoft.Blazor.RenderTree
             return index;
         }
 
-        private void Append(RenderTreeEdit entry)
+        private void Append(in RenderTreeEdit entry)
         {
             if (entry.Type == RenderTreeEditType.StepOut)
             {