From e7c1f402e7b170eb52acb66cba0aeb6aec485242 Mon Sep 17 00:00:00 2001
From: Ilia Sokolov <ilyusha.sokolov@gmail.com>
Date: Sun, 26 Jul 2026 09:41:01 +0200
Subject: [PATCH 1/2] Add time-to-first-content metric to reducer sample

---
 .../MultipleProviders_ChatHistoryReducer.cs   | 20 ++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/dotnet/samples/Concepts/ChatCompletion/MultipleProviders_ChatHistoryReducer.cs b/dotnet/samples/Concepts/ChatCompletion/MultipleProviders_ChatHistoryReducer.cs
index e3ee157b35b1..7bd3c6d900ca 100644
--- a/dotnet/samples/Concepts/ChatCompletion/MultipleProviders_ChatHistoryReducer.cs
+++ b/dotnet/samples/Concepts/ChatCompletion/MultipleProviders_ChatHistoryReducer.cs
@@ -1,5 +1,6 @@
 // Copyright (c) Microsoft. All rights reserved.
 
+using System.Diagnostics;
 using System.Text;
 using Microsoft.SemanticKernel.ChatCompletion;
 using Microsoft.SemanticKernel.Connectors.OpenAI;
@@ -124,16 +125,33 @@ public async Task ShowHowToReduceChatHistoryToLastMessageStreamingAsync()
             Console.WriteLine($"\n>>> User:\n{userMessage}");
 
             var response = new StringBuilder();
+            var timeToFirstContent = Stopwatch.StartNew();
+            var firstContentObserved = false;
             var chatUpdates = chatService.GetStreamingChatMessageContentsAsync(chatHistory);
             await foreach (var chatUpdate in chatUpdates)
             {
-                response.Append((string?)chatUpdate.Content);
+                var content = (string?)chatUpdate.Content;
+                response.Append(content);
+
+                if (!firstContentObserved && !string.IsNullOrEmpty(content))
+                {
+                    timeToFirstContent.Stop();
+                    firstContentObserved = true;
+                    Console.WriteLine(
+                        $"Time to first content, including chat-history reduction: {timeToFirstContent.ElapsedMilliseconds} ms");
+                }
 
                 if (chatUpdate.InnerContent is StreamingChatCompletionUpdate openAiChatUpdate)
                 {
                     totalTokenCount += openAiChatUpdate.Usage?.TotalTokenCount ?? 0;
                 }
             }
+
+            if (!firstContentObserved)
+            {
+                Console.WriteLine("Time to first content was not observed because the stream returned no text.");
+            }
+
             chatHistory.AddAssistantMessage(response.ToString());
             Console.WriteLine($"\n>>> Assistant:\n{response}");
         }

From 9e110d877a21ae39609e114c57dd2cce9e574300 Mon Sep 17 00:00:00 2001
From: Ilia Sokolov <ilyusha.sokolov@gmail.com>
Date: Thu, 30 Jul 2026 12:04:37 +0200
Subject: [PATCH 2/2] Report completion latency for textless streams

---
 .../ChatCompletion/MultipleProviders_ChatHistoryReducer.cs    | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/dotnet/samples/Concepts/ChatCompletion/MultipleProviders_ChatHistoryReducer.cs b/dotnet/samples/Concepts/ChatCompletion/MultipleProviders_ChatHistoryReducer.cs
index 7bd3c6d900ca..aa8d223b2bf8 100644
--- a/dotnet/samples/Concepts/ChatCompletion/MultipleProviders_ChatHistoryReducer.cs
+++ b/dotnet/samples/Concepts/ChatCompletion/MultipleProviders_ChatHistoryReducer.cs
@@ -149,7 +149,9 @@ public async Task ShowHowToReduceChatHistoryToLastMessageStreamingAsync()
 
             if (!firstContentObserved)
             {
-                Console.WriteLine("Time to first content was not observed because the stream returned no text.");
+                timeToFirstContent.Stop();
+                Console.WriteLine(
+                    $"No text content was observed; time to stream completion, including chat-history reduction: {timeToFirstContent.ElapsedMilliseconds} ms");
             }
 
             chatHistory.AddAssistantMessage(response.ToString());