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/Files/FileRequestHandler.cs

@@ -0,0 +1,53 @@
+using System.Threading.Tasks;
+
+namespace EmbedIO.Files
+{
+    /// <summary>
+    /// Provides standard handler callbacks for <see cref="FileModule"/>.
+    /// </summary>
+    /// <seealso cref="FileRequestHandlerCallback"/>
+    public static class FileRequestHandler
+    {
+#pragma warning disable CA1801 // Unused parameters - Must respect FileRequestHandlerCallback signature.
+        /// <summary>
+        /// <para>Unconditionally passes a request down the module chain.</para>
+        /// </summary>
+        /// <param name="context">An <see cref="IHttpContext"/> interface representing the context of the request.</param>
+        /// <param name="info">If the requested path has been successfully mapped to a resource (file or directory), the result of the mapping;
+        /// otherwise, <see langword="null"/>.</param>
+        /// <returns>This method never returns; it throws an exception instead.</returns>
+        public static Task PassThrough(IHttpContext context, MappedResourceInfo? info)
+            => throw RequestHandler.PassThrough();
+
+        /// <summary>
+        /// <para>Unconditionally sends a <c>403 Unauthorized</c> response.</para>
+        /// </summary>
+        /// <param name="context">An <see cref="IHttpContext"/> interface representing the context of the request.</param>
+        /// <param name="info">If the requested path has been successfully mapped to a resource (file or directory), the result of the mapping;
+        /// otherwise, <see langword="null"/>.</param>
+        /// <returns>This method never returns; it throws a <see cref="HttpException"/> instead.</returns>
+        public static Task ThrowUnauthorized(IHttpContext context, MappedResourceInfo? info)
+            => throw HttpException.Unauthorized();
+
+        /// <summary>
+        /// <para>Unconditionally sends a <c>404 Not Found</c> response.</para>
+        /// </summary>
+        /// <param name="context">An <see cref="IHttpContext"/> interface representing the context of the request.</param>
+        /// <param name="info">If the requested path has been successfully mapped to a resource (file or directory), the result of the mapping;
+        /// otherwise, <see langword="null"/>.</param>
+        /// <returns>This method never returns; it throws a <see cref="HttpException"/> instead.</returns>
+        public static Task ThrowNotFound(IHttpContext context, MappedResourceInfo? info)
+            => throw HttpException.NotFound();
+
+        /// <summary>
+        /// <para>Unconditionally sends a <c>405 Method Not Allowed</c> response.</para>
+        /// </summary>
+        /// <param name="context">An <see cref="IHttpContext"/> interface representing the context of the request.</param>
+        /// <param name="info">If the requested path has been successfully mapped to a resource (file or directory), the result of the mapping;
+        /// otherwise, <see langword="null"/>.</param>
+        /// <returns>This method never returns; it throws a <see cref="HttpException"/> instead.</returns>
+        public static Task ThrowMethodNotAllowed(IHttpContext context, MappedResourceInfo? info)
+            => throw HttpException.MethodNotAllowed();
+#pragma warning restore CA1801
+    }
+}