.Net: Prepare code for A2A SDK and AsyncEnumerable NuGet update

dotnet/Directory.Packages.props

@@ -85,7 +85,7 @@
     <PackageVersion Include="System.Diagnostics.DiagnosticSource" Version="8.0.1" />
     <PackageVersion Include="System.IdentityModel.Tokens.Jwt" Version="7.5.1" />
     <PackageVersion Include="System.IO.Packaging" Version="8.0.1" />
-    <PackageVersion Include="System.Linq.Async" Version="6.0.3" />
+    <PackageVersion Include="System.Linq.AsyncEnumerable" Version="10.0.0-preview.5.25277.114" />
     <PackageVersion Include="System.Memory.Data" Version="8.0.1" />
     <PackageVersion Include="System.Net.Http" Version="4.3.4" />
     <PackageVersion Include="System.Numerics.Tensors" Version="9.0.7" />

dotnet/samples/Concepts/Concepts.csproj

@@ -44,7 +44,6 @@
     <PackageReference Include="Microsoft.Extensions.Logging.Console" />
     <PackageReference Include="Microsoft.ML.Tokenizers" />
     <PackageReference Include="Microsoft.OpenApi" />
-    <PackageReference Include="System.Linq.Async" />
     <PackageReference Include="System.Numerics.Tensors" />
     <PackageReference Include="AWSSDK.Core" />
     <PackageReference Include="AWSSDK.SecurityToken" />
@@ -97,6 +96,10 @@
     <ProjectReference Include="..\..\src\SemanticKernel.Core\SemanticKernel.Core.csproj" />
   </ItemGroup>
 
+  <ItemGroup>
+    <Compile Include="$(RepoRoot)/dotnet/src/InternalUtilities/src/Linq/AsyncEnumerable.cs" Link="%(RecursiveDir)Utilities/%(Filename)%(Extension)" />
+  </ItemGroup>
+
   <ItemGroup>
     <Using Include="Xunit" />
     <Using Include="Xunit.Abstractions" />

dotnet/samples/Demos/ModelContextProtocolClientServer/MCPClient/MCPClient.csproj

@@ -13,6 +13,7 @@
     <PackageReference Include="Microsoft.Extensions.Configuration.EnvironmentVariables" />
     <PackageReference Include="Microsoft.Extensions.Configuration.UserSecrets" />
     <PackageReference Include="Microsoft.Extensions.Logging.Debug" />
+    <PackageReference Include="System.Linq.AsyncEnumerable" />
   </ItemGroup>
 
   <ItemGroup>

dotnet/samples/Demos/ModelContextProtocolPlugin/ModelContextProtocolPlugin.csproj

@@ -14,6 +14,7 @@
     <PackageReference Include="Microsoft.Extensions.Configuration.EnvironmentVariables" />
     <PackageReference Include="Microsoft.Extensions.Configuration.UserSecrets" />
     <PackageReference Include="Microsoft.Extensions.Logging.Debug" />
+    <PackageReference Include="System.Linq.AsyncEnumerable" />
   </ItemGroup>
 
   <ItemGroup>

dotnet/samples/Demos/ModelContextProtocolPluginAuth/ModelContextProtocolPluginAuth.csproj

@@ -15,8 +15,9 @@
     <PackageReference Include="Microsoft.Extensions.Configuration.UserSecrets" />
     <PackageReference Include="Microsoft.Extensions.Logging.Debug" />
     <PackageReference Include="Microsoft.Extensions.Logging.Console" />
+    <PackageReference Include="System.Linq.AsyncEnumerable" />
   </ItemGroup>
-  
+
   <ItemGroup>
     <ProjectReference Include="..\..\..\src\Agents\Abstractions\Agents.Abstractions.csproj" />
     <ProjectReference Include="..\..\..\src\Agents\Core\Agents.Core.csproj" />

dotnet/samples/GettingStarted/GettingStarted.csproj

@@ -47,7 +47,6 @@
     <PackageReference Include="Microsoft.Extensions.Logging" />
     <PackageReference Include="Microsoft.Extensions.Logging.Console" />
     <PackageReference Include="Microsoft.ML.Tokenizers" />
-    <PackageReference Include="System.Linq.Async" />
     <PackageReference Include="System.Numerics.Tensors" />
   </ItemGroup>
 

dotnet/samples/GettingStartedWithAgents/GettingStartedWithAgents.csproj

@@ -30,6 +30,7 @@
     <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" />
     <PackageReference Include="Microsoft.Extensions.Logging.Console" />
     <PackageReference Include="OpenTelemetry.Exporter.Console" />
+    <PackageReference Include="System.Linq.AsyncEnumerable" />
     <PackageReference Include="coverlet.collector" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" />
     <PackageReference Include="xunit" />

dotnet/samples/GettingStartedWithProcesses/GettingStartedWithProcesses.csproj

@@ -35,6 +35,7 @@
     <PackageReference Include="xunit" />
     <PackageReference Include="xunit.abstractions" />
     <PackageReference Include="xunit.runner.visualstudio" />
+    <PackageReference Include="System.Linq.AsyncEnumerable" />
   </ItemGroup>
 
   <Import Project="$(RepoRoot)/dotnet/src/InternalUtilities/samples/SamplesInternalUtilities.props" />

dotnet/samples/GettingStartedWithTextSearch/GettingStartedWithTextSearch.csproj

@@ -34,8 +34,8 @@
     <PackageReference Include="Microsoft.Extensions.Logging" />
     <PackageReference Include="Microsoft.Extensions.Logging.Console" />
     <PackageReference Include="Microsoft.ML.Tokenizers" />
-    <PackageReference Include="System.Linq.Async" />
     <PackageReference Include="System.Numerics.Tensors" />
+    <PackageReference Include="System.Linq.AsyncEnumerable" />
   </ItemGroup>
 
   <Import Project="$(RepoRoot)/dotnet/src/InternalUtilities/samples/SamplesInternalUtilities.props" />

dotnet/samples/GettingStartedWithVectorStores/GettingStartedWithVectorStores.csproj

@@ -32,8 +32,8 @@
     <PackageReference Include="Microsoft.Extensions.AI.OpenAI" />
     <PackageReference Include="Microsoft.Extensions.Logging" />
     <PackageReference Include="Microsoft.Extensions.Logging.Console" />
-    <PackageReference Include="System.Linq.Async" />
     <PackageReference Include="System.Text.Json" />
+    <PackageReference Include="System.Linq.AsyncEnumerable" />
   </ItemGroup>
 
   <Import Project="$(RepoRoot)/dotnet/src/InternalUtilities/samples/SamplesInternalUtilities.props" />

dotnet/samples/LearnResources/LearnResources.csproj

@@ -46,7 +46,6 @@
     <PackageReference Include="Microsoft.Extensions.Logging" />
     <PackageReference Include="Microsoft.Extensions.Logging.Console" />
     <PackageReference Include="Microsoft.Extensions.Logging.Debug" />
-    <PackageReference Include="System.Linq.Async" />
   </ItemGroup>
 
   <Import Project="$(RepoRoot)/dotnet/src/InternalUtilities/samples/SamplesInternalUtilities.props" />

dotnet/src/.editorconfig

@@ -1,5 +1,6 @@
 # Setting errors for SDK projects under dotnet folder
 [*.cs]
+dotnet_diagnostic.CS1998.severity = suggestion # Async method lacks 'await' operators and will run synchronously
 dotnet_diagnostic.CA2007.severity = error # Do not directly await a Task
 dotnet_diagnostic.VSTHRD111.severity = error # Use .ConfigureAwait(bool)
 dotnet_diagnostic.IDE1006.severity = error # Naming rule violations

dotnet/src/Agents/Abstractions/Agents.Abstractions.csproj

@@ -26,7 +26,6 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="System.Linq.Async" />
     <PackageReference Include="System.Text.Json" />
   </ItemGroup>
 

dotnet/src/Agents/Abstractions/AggregatorChannel.cs

@@ -1,7 +1,6 @@
 // Copyright (c) Microsoft. All rights reserved.
 using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
-using System.Linq;
 using System.Runtime.CompilerServices;
 using System.Text.Json;
 using System.Threading;
@@ -56,7 +55,11 @@ protected internal override IAsyncEnumerable<ChatMessageContent> GetHistoryAsync
     /// <inheritdoc/>
     protected internal override async IAsyncEnumerable<StreamingChatMessageContent> InvokeStreamingAsync(AggregatorAgent agent, IList<ChatMessageContent> messages, [EnumeratorCancellation] CancellationToken cancellationToken = default)
     {
-        int initialCount = await this._chat.GetChatMessagesAsync(cancellationToken).CountAsync(cancellationToken).ConfigureAwait(false);
+        int initialCount = 0;
+        await foreach (var _ in this._chat.GetChatMessagesAsync(cancellationToken).ConfigureAwait(false))
+        {
+            initialCount++;
+        }
 
         await foreach (StreamingChatMessageContent message in this._chat.InvokeStreamingAsync(cancellationToken).ConfigureAwait(false))
         {
@@ -66,12 +69,17 @@ protected internal override async IAsyncEnumerable<StreamingChatMessageContent>
             }
         }
 
-        ChatMessageContent[] history = await this._chat.GetChatMessagesAsync(cancellationToken).ToArrayAsync(cancellationToken).ConfigureAwait(false);
-        if (history.Length > initialCount)
+        List<ChatMessageContent> history = [];
+        await foreach (var item in this._chat.GetChatMessagesAsync(cancellationToken).ConfigureAwait(false))
+        {
+            history.Add(item);
+        }
+
+        if (history.Count > initialCount)
         {
             if (agent.Mode == AggregatorMode.Flat)
             {
-                for (int index = history.Length - 1; index >= initialCount; --index)
+                for (int index = history.Count - 1; index >= initialCount; --index)
                 {
                     messages.Add(history[index]);
                 }

dotnet/src/Agents/Abstractions/Extensions/ChatHistoryExtensions.cs

@@ -1,6 +1,5 @@
 // Copyright (c) Microsoft. All rights reserved.
 using System.Collections.Generic;
-using System.Linq;
 using Microsoft.SemanticKernel.ChatCompletion;
 
 namespace Microsoft.SemanticKernel.Agents.Extensions;
@@ -26,8 +25,11 @@ public static IEnumerable<ChatMessageContent> ToDescending(this ChatHistory hist
     /// Enumerates a history in descending order asynchronously.
     /// </summary>
     /// <param name="history">The chat history to sort.</param>
-    public static IAsyncEnumerable<ChatMessageContent> ToDescendingAsync(this ChatHistory history)
+    public static async IAsyncEnumerable<ChatMessageContent> ToDescendingAsync(this ChatHistory history)
     {
-        return history.ToDescending().ToAsyncEnumerable();
+        for (int index = history.Count; index > 0; --index)
+        {
+            yield return history[index - 1];
+        }
     }
 }

dotnet/src/Agents/AzureAI/Internal/AgentThreadActions.cs

@@ -181,7 +181,11 @@ public static async IAsyncEnumerable<ChatMessageContent> GetMessagesAsync(Persis
                 throw new KernelException($"Agent Failure - Run terminated: {run.Status} [{run.Id}]: {run.LastError?.Message ?? "Unknown"}");
             }
 
-            RunStep[] steps = await client.GetStepsAsync(run, cancellationToken: cancellationToken).ToArrayAsync(cancellationToken).ConfigureAwait(false);
+            List<RunStep> steps = [];
+            await foreach (var step in client.GetStepsAsync(run, cancellationToken: cancellationToken).ConfigureAwait(false))
+            {
+                steps.Add(step);
+            }
 
             // Is tool action required?
             if (run.Status == RunStatus.RequiresAction)
@@ -204,7 +208,7 @@ await functionProcessor.InvokeFunctionCallsAsync(
                             functionOptions,
                             kernel,
                             isStreaming: false,
-                            cancellationToken).ToArrayAsync(cancellationToken).ConfigureAwait(false);
+                            cancellationToken).ConfigureAwait(false);
 
                     // Capture function-call for message processing
                     foreach (FunctionResultContent functionCall in functionResults)
@@ -458,10 +462,14 @@ public static async IAsyncEnumerable<StreamingChatMessageContent> InvokeStreamin
 
             if (run.Status == RunStatus.RequiresAction)
             {
-                RunStep[] activeSteps =
-                    await client.GetStepsAsync(run, cancellationToken)
-                    .Where(step => step.Status == RunStepStatus.InProgress)
-                    .ToArrayAsync(cancellationToken).ConfigureAwait(false);
+                List<RunStep> activeSteps = [];
+                await foreach (var step in client.GetStepsAsync(run, cancellationToken).ConfigureAwait(false))
+                {
+                    if (step.Status == RunStepStatus.InProgress)
+                    {
+                        activeSteps.Add(step);
+                    }
+                }
 
                 // Capture map between the tool call and its associated step
                 Dictionary<string, string> toolMap = [];
@@ -489,7 +497,7 @@ await functionProcessor.InvokeFunctionCallsAsync(
                             functionOptions,
                             kernel,
                             isStreaming: true,
-                            cancellationToken).ToArrayAsync(cancellationToken).ConfigureAwait(false);
+                            cancellationToken).ConfigureAwait(false);
 
                     // Process tool output
                     ToolOutput[] toolOutputs = GenerateToolOutputs(functionResults);

dotnet/src/Agents/Bedrock/Extensions/BedrockAgentInvokeExtensions.cs

@@ -44,7 +44,7 @@ public static async IAsyncEnumerable<ChatMessageContent> InternalInvokeAsync(
             }
 
             List<FunctionCallContent> functionCallContents = [];
-            await foreach (var responseEvent in invokeAgentResponse.Completion.ToAsyncEnumerable().ConfigureAwait(false))
+            foreach (var responseEvent in invokeAgentResponse.Completion)
             {
                 if (responseEvent is BedrockAgentRuntimeEventStreamException bedrockAgentRuntimeEventStreamException)
                 {

dotnet/src/Agents/Core/Functions/AgentKernelFunctionFactory.cs

@@ -53,8 +53,12 @@ async Task<FunctionResult> InvokeAgentAsync(Kernel kernel, KernelFunction functi
             }
 
             var response = agent.InvokeAsync(new ChatMessageContent(AuthorRole.User, queryString), null, options, cancellationToken);
-            var responseItems = await response.ToArrayAsync(cancellationToken: cancellationToken).ConfigureAwait(false);
-            var chatMessages = responseItems.Select(i => i.Message).ToArray();
+
+            List<ChatMessageContent> chatMessages = [];
+            await foreach (var item in response.WithCancellation(cancellationToken).ConfigureAwait(false))
+            {
+                chatMessages.Add(item.Message);
+            }
             return new FunctionResult(function, chatMessages, kernel.Culture);
         }
 

dotnet/src/Agents/OpenAI/Internal/AssistantThreadActions.cs

@@ -164,7 +164,11 @@ public static async IAsyncEnumerable<ChatMessageContent> GetMessagesAsync(Assist
                 throw new KernelException($"Agent Failure - Run terminated: {run.Status} [{run.Id}]: {run.LastError?.Message ?? "Unknown"}");
             }
 
-            RunStep[] steps = await client.GetRunStepsAsync(run.ThreadId, run.Id, cancellationToken: cancellationToken).ToArrayAsync(cancellationToken).ConfigureAwait(false);
+            List<RunStep> steps = [];
+            await foreach (var step in client.GetRunStepsAsync(run.ThreadId, run.Id, cancellationToken: cancellationToken).ConfigureAwait(false))
+            {
+                steps.Add(step);
+            }
 
             // Is tool action required?
             if (run.Status == RunStatus.RequiresAction)
@@ -187,7 +191,7 @@ await functionProcessor.InvokeFunctionCallsAsync(
                             functionOptions,
                             kernel,
                             isStreaming: false,
-                            cancellationToken).ToArrayAsync(cancellationToken).ConfigureAwait(false);
+                            cancellationToken).ConfigureAwait(false);
 
                     // Capture function-call for message processing
                     foreach (FunctionResultContent functionCall in functionResults)
@@ -453,10 +457,14 @@ public static async IAsyncEnumerable<StreamingChatMessageContent> InvokeStreamin
 
             if (run.Status == RunStatus.RequiresAction)
             {
-                RunStep[] activeSteps =
-                    await client.GetRunStepsAsync(run.ThreadId, run.Id, cancellationToken: cancellationToken)
-                    .Where(step => step.Status == RunStepStatus.InProgress)
-                    .ToArrayAsync(cancellationToken).ConfigureAwait(false);
+                List<RunStep> activeSteps = [];
+                await foreach (var step in client.GetRunStepsAsync(run.ThreadId, run.Id, cancellationToken: cancellationToken).ConfigureAwait(false))
+                {
+                    if (step.Status == RunStepStatus.InProgress)
+                    {
+                        activeSteps.Add(step);
+                    }
+                }
 
                 // Capture map between the tool call and its associated step
                 Dictionary<string, string> toolMap = [];
@@ -483,7 +491,7 @@ await functionProcessor.InvokeFunctionCallsAsync(
                             functionOptions,
                             kernel,
                             isStreaming: true,
-                            cancellationToken).ToArrayAsync(cancellationToken).ConfigureAwait(false);
+                            cancellationToken).ConfigureAwait(false);
 
                     // Process tool output
                     ToolOutput[] toolOutputs = GenerateToolOutputs(functionResults);

dotnet/src/Agents/OpenAI/Internal/ResponseThreadActions.cs

@@ -88,7 +88,7 @@ await functionProcessor.InvokeFunctionCallsAsync(
                     functionOptions,
                     agent.GetKernel(options),
                     isStreaming: false,
-                    cancellationToken).ToArrayAsync(cancellationToken).ConfigureAwait(false);
+                    cancellationToken).ConfigureAwait(false);
             var functionOutputItems = functionResults.Select(fr => ResponseItem.CreateFunctionCallOutputItem(fr.CallId, fr.Result?.ToString() ?? string.Empty)).ToList();
 
             // If store is enabled we only need to send the function output items
@@ -259,7 +259,7 @@ await functionProcessor.InvokeFunctionCallsAsync(
                     functionOptions,
                     agent.GetKernel(options),
                     isStreaming: true,
-                    cancellationToken).ToArrayAsync(cancellationToken).ConfigureAwait(false);
+                    cancellationToken).ConfigureAwait(false);
             var functionOutputItems = functionResults.Select(fr => ResponseItem.CreateFunctionCallOutputItem(fr.CallId, fr.Result?.ToString() ?? string.Empty)).ToList();
 
             // If store is enabled we only need to send the function output items

dotnet/src/Agents/Orchestration/AgentActor.cs

@@ -2,7 +2,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.Extensions.Logging;
@@ -123,14 +122,19 @@ async Task HandleMessageAsync(ChatMessageContent message)
 
     private async Task InvokeAsync(IList<ChatMessageContent> input, AgentInvokeOptions options, CancellationToken cancellationToken)
     {
-        AgentResponseItem<ChatMessageContent>? lastResponse =
-            await this.Agent.InvokeAsync(
-                input,
-                this.Thread,
-                options,
-                cancellationToken).LastOrDefaultAsync(cancellationToken).ConfigureAwait(false);
+        var last = default(AgentResponseItem<ChatMessageContent>)!;
+        var hasLast = false;
+
+        await foreach (var item in this.Agent.InvokeAsync(input, this.Thread, options, cancellationToken).ConfigureAwait(false))
+        {
+            hasLast = true;
+            last = item;
+        }
 
-        this.Thread ??= lastResponse?.Thread;
+        if (this.Thread is null && hasLast)
+        {
+            this.Thread = last.Thread;
+        }
     }
 
     private async Task InvokeStreamingAsync(IList<ChatMessageContent> input, AgentInvokeOptions options, CancellationToken cancellationToken)

dotnet/src/Agents/Runtime/Abstractions/Runtime.Abstractions.csproj

@@ -32,7 +32,6 @@
   </ItemGroup>
 
   <ItemGroup>
-    <InternalsVisibleTo Include="Microsoft.SemanticKernel.Agents.Runtime.Abstractions.Tests" />
     <InternalsVisibleTo Include="DynamicProxyGenAssembly2" />
   </ItemGroup>
 

dotnet/src/Agents/UnitTests/Agents.UnitTests.csproj

@@ -24,6 +24,7 @@
     <PackageReference Include="Microsoft.Extensions.Http.Resilience" VersionOverride="9.1.0" />
     <PackageReference Include="Microsoft.Extensions.Logging" VersionOverride="9.0.5" />
     <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" VersionOverride="9.0.5" />
+		<PackageReference Include="System.Linq.AsyncEnumerable" />
     <PackageReference Include="Moq" />
     <PackageReference Include="xunit" />
     <PackageReference Include="xunit.runner.visualstudio">

dotnet/src/Agents/Yaml/Agents.Yaml.csproj

@@ -33,7 +33,6 @@
   </ItemGroup>
 
   <ItemGroup>
-    <InternalsVisibleTo Include="SemanticKernel.Agents.UnitTests" />
     <InternalsVisibleTo Include="DynamicProxyGenAssembly2" />
   </ItemGroup>
 

dotnet/src/Experimental/Process.IntegrationTestRunner.Dapr/Process.IntegrationTestRunner.Dapr.csproj

@@ -31,7 +31,6 @@
     <PackageReference Include="Microsoft.Extensions.Http.Resilience" />
     <PackageReference Include="Microsoft.Extensions.TimeProvider.Testing" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" />
-    <PackageReference Include="System.Linq.Async" />
     <PackageReference Include="xRetry" />
     <PackageReference Include="xunit" />
     <PackageReference Include="xunit.runner.visualstudio">