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/Routing/SyncRouteHandlerCallback.cs

@@ -0,0 +1,10 @@
+namespace EmbedIO.Routing
+{
+    /// <summary>
+    /// Base class for callbacks used to handle routed requests synchronously.
+    /// </summary>
+    /// <param name="context">An <see cref="IHttpContext" /> interface representing the context of the request.</param>
+    /// <param name="route">The matched route.</param>
+    /// <seealso cref="RouteMatch"/>
+    public delegate void SyncRouteHandlerCallback(IHttpContext context, RouteMatch route);
+}