Implement SEP-2663 Tasks Extension (#1579)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/ModelContextProtocol.Core/Server/InputResponseReceivedEventArgs.cs

@@ -0,0 +1,26 @@
+using ModelContextProtocol.Protocol;
+using System.Diagnostics.CodeAnalysis;
+
+namespace ModelContextProtocol.Server;
+
+/// <summary>
+/// Provides data for the <see cref="IMcpTaskStore.InputResponseReceived"/> event.
+/// </summary>
+[Experimental(Experimentals.Extensions_DiagnosticId, UrlFormat = Experimentals.Extensions_Url)]
+public sealed class InputResponseReceivedEventArgs
+{
+    /// <summary>
+    /// Gets the task identifier.
+    /// </summary>
+    public required string TaskId { get; init; }
+
+    /// <summary>
+    /// Gets the request identifier that was resolved.
+    /// </summary>
+    public required string RequestId { get; init; }
+
+    /// <summary>
+    /// Gets the response payload.
+    /// </summary>
+    public required InputResponse Response { get; init; }
+}