.NET: Change type of props representing continuation token (#2430)

* change type of props representing continuation token

* use explict cast instead of the as operator

dotnet/samples/GettingStarted/Agents/Agent_Step13_BackgroundResponsesWithToolsAndPersistence/Program.cs

@@ -44,7 +44,7 @@ while (response.ContinuationToken is not null)
 
     await Task.Delay(TimeSpan.FromSeconds(10));
 
-    RestoreAgentState(agent, out thread, out object? continuationToken);
+    RestoreAgentState(agent, out thread, out ResponseContinuationToken? continuationToken);
 
     options.ContinuationToken = continuationToken;
     response = await agent.RunAsync(thread, options);
@@ -52,19 +52,19 @@ while (response.ContinuationToken is not null)
 
 Console.WriteLine(response.Text);
 
-void PersistAgentState(AgentThread thread, object? continuationToken)
+void PersistAgentState(AgentThread thread, ResponseContinuationToken? continuationToken)
 {
     stateStore["thread"] = thread.Serialize();
     stateStore["continuationToken"] = JsonSerializer.SerializeToElement(continuationToken, AgentAbstractionsJsonUtilities.DefaultOptions.GetTypeInfo(typeof(ResponseContinuationToken)));
 }
 
-void RestoreAgentState(AIAgent agent, out AgentThread thread, out object? continuationToken)
+void RestoreAgentState(AIAgent agent, out AgentThread thread, out ResponseContinuationToken? continuationToken)
 {
     JsonElement serializedThread = stateStore["thread"] ?? throw new InvalidOperationException("No serialized thread found in state store.");
     JsonElement? serializedToken = stateStore["continuationToken"];
 
     thread = agent.DeserializeThread(serializedThread);
-    continuationToken = serializedToken?.Deserialize(AgentAbstractionsJsonUtilities.DefaultOptions.GetTypeInfo(typeof(ResponseContinuationToken)));
+    continuationToken = (ResponseContinuationToken?)serializedToken?.Deserialize(AgentAbstractionsJsonUtilities.DefaultOptions.GetTypeInfo(typeof(ResponseContinuationToken)));
 }
 
 [Description("Researches relevant space facts and scientific information for writing a science fiction novel")]

dotnet/src/Microsoft.Agents.AI.Abstractions/AgentRunOptions.cs

@@ -49,7 +49,7 @@ public class AgentRunOptions
     /// can be polled for completion by obtaining the token from the <see cref="AgentRunResponse.ContinuationToken"/> property
     /// and passing it via this property on subsequent calls to <see cref="AIAgent.RunAsync(AgentThread?, AgentRunOptions?, System.Threading.CancellationToken)"/>.
     /// </remarks>
-    public object? ContinuationToken { get; set; }
+    public ResponseContinuationToken? ContinuationToken { get; set; }
 
     /// <summary>
     /// Gets or sets a value indicating whether the background responses are allowed.

dotnet/src/Microsoft.Agents.AI.Abstractions/AgentRunResponse.cs

@@ -175,7 +175,7 @@ public class AgentRunResponse
     /// to poll for completion.
     /// </para>
     /// </remarks>
-    public object? ContinuationToken { get; set; }
+    public ResponseContinuationToken? ContinuationToken { get; set; }
 
     /// <summary>
     /// Gets or sets the timestamp indicating when this response was created.

dotnet/src/Microsoft.Agents.AI.Abstractions/AgentRunResponseExtensions.cs

@@ -42,7 +42,7 @@ public static class AgentRunResponseExtensions
                 RawRepresentation = response,
                 ResponseId = response.ResponseId,
                 Usage = response.Usage,
-                ContinuationToken = response.ContinuationToken as ResponseContinuationToken,
+                ContinuationToken = response.ContinuationToken,
             };
     }
 
@@ -75,7 +75,7 @@ public static class AgentRunResponseExtensions
                 RawRepresentation = responseUpdate,
                 ResponseId = responseUpdate.ResponseId,
                 Role = responseUpdate.Role,
-                ContinuationToken = responseUpdate.ContinuationToken as ResponseContinuationToken,
+                ContinuationToken = responseUpdate.ContinuationToken,
             };
     }
 

dotnet/src/Microsoft.Agents.AI.Abstractions/AgentRunResponseUpdate.cs

@@ -159,7 +159,7 @@ public class AgentRunResponseUpdate
     /// to resume streaming from the point of interruption.
     /// </para>
     /// </remarks>
-    public object? ContinuationToken { get; set; }
+    public ResponseContinuationToken? ContinuationToken { get; set; }
 
     /// <inheritdoc/>
     public override string ToString() => this.Text;

dotnet/src/Microsoft.Agents.AI/ChatClient/ChatClientAgent.cs

@@ -551,7 +551,7 @@ public sealed partial class ChatClientAgent : AIAgent
             {
                 chatOptions ??= new ChatOptions();
                 chatOptions.AllowBackgroundResponses = agentRunOptions.AllowBackgroundResponses;
-                chatOptions.ContinuationToken = agentRunOptions.ContinuationToken as ResponseContinuationToken;
+                chatOptions.ContinuationToken = agentRunOptions.ContinuationToken;
             }
 
             return chatOptions;

dotnet/tests/Microsoft.Agents.AI.Abstractions.UnitTests/AgentRunOptionsTests.cs

@@ -17,7 +17,7 @@ public class AgentRunOptionsTests
         // Arrange
         var options = new AgentRunOptions
         {
-            ContinuationToken = new object(),
+            ContinuationToken = ResponseContinuationToken.FromBytes(new byte[] { 1, 2, 3 }),
             AllowBackgroundResponses = true,
             AdditionalProperties = new AdditionalPropertiesDictionary
             {

dotnet/tests/Microsoft.Agents.AI.Workflows.UnitTests/Sample/10_Sequential_HostAsAgent.cs

@@ -25,7 +25,7 @@ internal static class Step10EntryPoint
         foreach (string input in inputs)
         {
             AgentRunResponse response;
-            object? continuationToken = null;
+            ResponseContinuationToken? continuationToken = null;
             do
             {
                 response = await hostAgent.RunAsync(input, thread, new AgentRunOptions { ContinuationToken = continuationToken });

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

@@ -37,7 +37,7 @@ internal static class Step11EntryPoint
         foreach (string input in inputs)
         {
             AgentRunResponse response;
-            object? continuationToken = null;
+            ResponseContinuationToken? continuationToken = null;
             do
             {
                 response = await hostAgent.RunAsync(input, thread, new AgentRunOptions { ContinuationToken = continuationToken });

dotnet/tests/Microsoft.Agents.AI.Workflows.UnitTests/Sample/12_HandOff_HostAsAgent.cs

@@ -73,7 +73,7 @@ internal static class Step12EntryPoint
         foreach (string input in inputs)
         {
             AgentRunResponse response;
-            object? continuationToken = null;
+            ResponseContinuationToken? continuationToken = null;
             do
             {
                 response = await hostAgent.RunAsync(input, thread, new AgentRunOptions { ContinuationToken = continuationToken });