Got at least one data fetching method working; turns out, we can't use a patched LogicStack to get the data

Vendor/EmbedIO-3.5.2/WebServerExtensions-SessionManager.cs

@@ -0,0 +1,43 @@
+using System;
+using EmbedIO.Sessions;
+
+namespace EmbedIO
+{
+    partial class WebServerExtensions
+    {
+        /// <summary>
+        /// Sets the session manager on an <see cref="IWebServer"/>.
+        /// </summary>
+        /// <typeparam name="TWebServer">The type of the web server.</typeparam>
+        /// <param name="this">The <see cref="IWebServer"/> on which this method is called.</param>
+        /// <param name="sessionManager">The session manager.</param>
+        /// <returns><paramref name="this"/> with the session manager set.</returns>
+        /// <exception cref="NullReferenceException"><paramref name="this"/> is <see langword="null"/>.</exception>
+        /// <exception cref="InvalidOperationException">The web server has already been started.</exception>
+        public static TWebServer WithSessionManager<TWebServer>(this TWebServer @this, ISessionManager sessionManager)
+            where TWebServer : IWebServer
+        {
+            @this.SessionManager = sessionManager;
+            return @this;
+        }
+
+        /// <summary>
+        /// <para>Creates a <see cref="LocalSessionManager"/> with all properties set to their default values
+        /// and sets it as session manager on an <see cref="IWebServer"/>.</para>
+        /// </summary>
+        /// <typeparam name="TWebServer">The type of the web server.</typeparam>
+        /// <param name="this">The <see cref="IWebServer"/> on which this method is called.</param>
+        /// <param name="configure">A callback used to configure the session manager.</param>
+        /// <returns><paramref name="this"/> with the session manager set.</returns>
+        /// <exception cref="NullReferenceException"><paramref name="this"/> is <see langword="null"/>.</exception>
+        /// <exception cref="InvalidOperationException">The web server has already been started.</exception>
+        public static TWebServer WithLocalSessionManager<TWebServer>(this TWebServer @this, Action<LocalSessionManager>? configure = null)
+            where TWebServer : IWebServer
+        {
+            var sessionManager = new LocalSessionManager();
+            configure?.Invoke(sessionManager);
+            @this.SessionManager = sessionManager;
+            return @this;
+        }
+    }
+}