Fix Observability/WorkflowAsAnAgent sampl (#6316)

dotnet/samples/03-workflows/Observability/WorkflowAsAnAgent/WorkflowHelper.cs

@@ -50,12 +50,16 @@ internal static partial class WorkflowHelper
     /// <summary>
     /// Executor that starts the concurrent processing by sending messages to the agents.
     /// </summary>
-    private sealed partial class ConcurrentStartExecutor() : Executor("ConcurrentStartExecutor")
+    [SendsMessage(typeof(List<ChatMessage>))]
+    [SendsMessage(typeof(TurnToken))]
+    private sealed partial class ConcurrentStartExecutor()
+        : Executor("ConcurrentStartExecutor", declareCrossRunShareable: true), IResettableExecutor
     {
         [MessageHandler]
-        internal ValueTask RouteMessages(List<ChatMessage> messages, IWorkflowContext context, CancellationToken cancellationToken)
+        internal ValueTask RouteMessages(IEnumerable<ChatMessage> messages, IWorkflowContext context, CancellationToken cancellationToken)
         {
-            return context.SendMessageAsync(messages, cancellationToken: cancellationToken);
+            List<ChatMessage> payload = messages as List<ChatMessage> ?? messages.ToList();
+            return context.SendMessageAsync(payload, cancellationToken: cancellationToken);
         }
 
         [MessageHandler]
@@ -63,13 +67,16 @@ internal static partial class WorkflowHelper
         {
             return context.SendMessageAsync(token, cancellationToken: cancellationToken);
         }
+
+        public ValueTask ResetAsync() => default;
     }
 
     /// <summary>
     /// Executor that aggregates the results from the concurrent agents.
     /// </summary>
-    [YieldsOutput(typeof(List<ChatMessage>))]
-    private sealed partial class ConcurrentAggregationExecutor() : Executor<List<ChatMessage>>("ConcurrentAggregationExecutor")
+    [YieldsOutput(typeof(string))]
+    private sealed partial class ConcurrentAggregationExecutor() :
+        Executor<List<ChatMessage>>("ConcurrentAggregationExecutor"), IResettableExecutor
     {
         private readonly List<ChatMessage> _messages = [];
 
@@ -90,5 +97,11 @@ internal static partial class WorkflowHelper
                 await context.YieldOutputAsync(formattedMessages, cancellationToken);
             }
         }
+
+        public ValueTask ResetAsync()
+        {
+            this._messages.Clear();
+            return default;
+        }
     }
 }