Address async review feedback: Emit indirection, FlushSafe logging, CancellationToken propagation in McpClientPlugin

Libraries/Microsoft.Teams.AI/Stream.cs

@@ -39,7 +39,7 @@ public class Stream(OnStreamChunk onChunk) : IStream
     [Obsolete("Use EmitAsync instead to avoid sync-over-async blocking.")]
     public void Emit(string text)
     {
-        EmitAsync(text).ConfigureAwait(false).GetAwaiter().GetResult();
+        onChunk(text).GetAwaiter().GetResult();
     }
 
     public Task EmitAsync(string text)

Libraries/Microsoft.Teams.Plugins/Microsoft.Teams.Plugins.AspNetCore/AspNetCorePlugin.Stream.cs

@@ -7,6 +7,7 @@
 using Microsoft.Teams.Api.Activities;
 using Microsoft.Teams.Api.Entities;
 using Microsoft.Teams.Apps.Plugins;
+using Microsoft.Teams.Common.Logging;
 
 using static Microsoft.Teams.Common.Extensions.TaskExtensions;
 
@@ -21,6 +22,7 @@ public class Stream : IStreamer
         public int Sequence => _index;
 
         public required Func<IActivity, Task<IActivity>> Send { get; set; }
+        public ILogger? Logger { get; set; }
         public event IStreamer.OnChunkHandler OnChunk = (_) => { };
 
         protected int _index = 1;
@@ -215,8 +217,9 @@ private async Task FlushSafe()
             {
                 await Flush().ConfigureAwait(false);
             }
-            catch (Exception)
+            catch (Exception ex)
             {
+                Logger?.Warn("Stream flush failed; will retry if there is pending state.", ex);
                 // Reschedule a retry so Close() doesn't spin forever
                 // waiting for _id to be set after a transient send failure.
                 if (_queue.Count > 0 || _id is null && _count > 0)

Libraries/Microsoft.Teams.Plugins/Microsoft.Teams.Plugins.AspNetCore/AspNetCorePlugin.cs

@@ -138,7 +138,8 @@ public IStreamer CreateStream(Api.ConversationReference reference, CancellationT
             {
                 var res = await Send(activity, reference, cancellationToken).ConfigureAwait(false);
                 return res;
-            }
+            },
+            Logger = Logger.Child("stream")
         };
     }
 

Libraries/Microsoft.Teams.Plugins/Microsoft.Teams.Plugins.External/Microsoft.Teams.Plugins.External.McpClient/McpClientPlugin.cs

@@ -70,7 +70,7 @@ public McpClientPlugin UseMcpServer(string url, McpClientPluginParams? pluginPar
 
     public override async Task<FunctionCollection> OnBuildFunctions<TOptions>(IChatPrompt<TOptions> prompt, FunctionCollection functions, CancellationToken cancellationToken = default)
     {
-        await FetchToolsIfNeeded().ConfigureAwait(false);
+        await FetchToolsIfNeeded(cancellationToken).ConfigureAwait(false);
 
         foreach (var entry in _mcpServerParams)
         {
@@ -100,7 +100,7 @@ public override async Task<FunctionCollection> OnBuildFunctions<TOptions>(IChatP
     /// 
     /// Checks if cached values have expired or if tools have never been fetched. Performs parallel fetching for efficiency.
     /// </summary>
-    internal async Task FetchToolsIfNeeded()
+    internal async Task FetchToolsIfNeeded(CancellationToken cancellationToken = default)
     {
         var fetchNeeded = new List<KeyValuePair<string, McpClientPluginParams>>();
 
@@ -132,7 +132,7 @@ internal async Task FetchToolsIfNeeded()
             {
                 string url = entry.Key;
                 McpClientPluginParams pluginParams = entry.Value;
-                tasks.Add(FetchToolsFromServer(new Uri(url), pluginParams));
+                tasks.Add(FetchToolsFromServer(new Uri(url), pluginParams, cancellationToken));
             }
             try
             {
@@ -179,11 +179,11 @@ internal async Task FetchToolsIfNeeded()
         }
     }
 
-    internal async Task<List<McpToolDetails>> FetchToolsFromServer(Uri url, McpClientPluginParams pluginParams)
+    internal async Task<List<McpToolDetails>> FetchToolsFromServer(Uri url, McpClientPluginParams pluginParams, CancellationToken cancellationToken = default)
     {
         IClientTransport transport = CreateTransport(url, pluginParams.Transport, pluginParams.HeadersFactory());
-        var client = await McpClientFactory.CreateAsync(transport).ConfigureAwait(false);
-        var tools = await client.ListToolsAsync().ConfigureAwait(false);
+        var client = await McpClientFactory.CreateAsync(transport, cancellationToken: cancellationToken).ConfigureAwait(false);
+        var tools = await client.ListToolsAsync(cancellationToken: cancellationToken).ConfigureAwait(false);
 
         // Convert MCP tools to our format
         var mappedTools = tools.Select(t => new McpToolDetails()