chore: import upstream snapshot with attribution

dotnet/tests/Microsoft.Agents.AI.Workflows.UnitTests/Sample/11_Concurrent_HostAsAgent.cs

@@ -0,0 +1,52 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Threading.Tasks;
+using Microsoft.Agents.AI.Workflows.UnitTests;
+using Microsoft.Extensions.AI;
+
+namespace Microsoft.Agents.AI.Workflows.Sample;
+
+internal static class Step11EntryPoint
+{
+    public const int AgentCount = 2;
+
+    public const string EchoAgentIdPrefix = "echo-";
+    public const string EchoAgentNamePrefix = "Echo";
+
+    public static string ExpectedOutputForInput(string input, int agentNumber)
+        => $"{EchoAgentNamePrefix}{agentNumber}: {input}";
+
+    public static Workflow CreateWorkflow()
+    {
+        TestEchoAgent[] echoAgents = Enumerable.Range(1, AgentCount)
+            .Select(i => new TestEchoAgent($"{EchoAgentIdPrefix}{i}", $"{EchoAgentNamePrefix}{i}"))
+            .ToArray();
+
+        return AgentWorkflowBuilder.BuildConcurrent(echoAgents);
+    }
+    public static Workflow WorkflowInstance => CreateWorkflow();
+
+    public static async ValueTask RunAsync(TextWriter writer, IWorkflowExecutionEnvironment executionEnvironment, IEnumerable<string> inputs)
+    {
+        AIAgent hostAgent = WorkflowInstance.AsAIAgent("echo-workflow", "EchoW", executionEnvironment: executionEnvironment);
+
+        AgentSession session = await hostAgent.CreateSessionAsync();
+        foreach (string input in inputs)
+        {
+            AgentResponse response;
+            ResponseContinuationToken? continuationToken = null;
+            do
+            {
+                response = await hostAgent.RunAsync(input, session, new AgentRunOptions { ContinuationToken = continuationToken });
+            } while ((continuationToken = response.ContinuationToken) is { });
+
+            foreach (ChatMessage message in response.Messages)
+            {
+                writer.WriteLine($"{message.AuthorName}: {message.Text}");
+            }
+        }
+    }
+}