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/ResourceFileProvider.cs

@@ -0,0 +1,94 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Reflection;
+using System.Threading;
+using EmbedIO.Utilities;
+
+namespace EmbedIO.Files
+{
+    /// <summary>
+    /// Provides access to embedded resources to a <see cref="FileModule"/>.
+    /// </summary>
+    /// <seealso cref="IFileProvider" />
+    public class ResourceFileProvider : IFileProvider
+    {
+        private readonly DateTime _fileTime = DateTime.UtcNow;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="ResourceFileProvider"/> class.
+        /// </summary>
+        /// <param name="assembly">The assembly where served files are contained as embedded resources.</param>
+        /// <param name="pathPrefix">A string to prepend to provider-specific paths
+        /// to form the name of a manifest resource in <paramref name="assembly"/>.</param>
+        /// <exception cref="ArgumentNullException"><paramref name="assembly"/> is <see langword="null"/>.</exception>
+        public ResourceFileProvider(Assembly assembly, string pathPrefix)
+        {
+            Assembly = Validate.NotNull(nameof(assembly), assembly);
+            PathPrefix = pathPrefix ?? string.Empty;
+        }
+
+        /// <inheritdoc />
+        public event Action<string> ResourceChanged
+        {
+            add { }
+            remove { }
+        }
+
+        /// <summary>
+        /// Gets the assembly where served files are contained as embedded resources.
+        /// </summary>
+        public Assembly Assembly { get; }
+
+        /// <summary>
+        /// Gets a string that is prepended to provider-specific paths to form the name of a manifest resource in <see cref="Assembly"/>.
+        /// </summary>
+        public string PathPrefix { get; }
+
+        /// <inheritdoc />
+        public bool IsImmutable => true;
+
+        /// <inheritdoc />
+        public void Start(CancellationToken cancellationToken)
+        {
+        }
+
+        /// <inheritdoc />
+        public MappedResourceInfo? MapUrlPath(string urlPath, IMimeTypeProvider mimeTypeProvider)
+        {
+            var resourceName = PathPrefix + urlPath.Replace('/', '.');
+
+            long size;
+            try
+            {
+                using var stream = Assembly.GetManifestResourceStream(resourceName);
+                if (stream == null || stream == Stream.Null)
+                    return null;
+
+                size = stream.Length;
+            }
+            catch (FileNotFoundException)
+            {
+                return null;
+            }
+
+            var lastSlashPos = urlPath.LastIndexOf('/');
+            var name = urlPath.Substring(lastSlashPos + 1);
+
+            return MappedResourceInfo.ForFile(
+                resourceName, 
+                name, 
+                _fileTime, 
+                size, 
+                mimeTypeProvider.GetMimeType(Path.GetExtension(name)));
+        }
+
+        /// <inheritdoc />
+        public Stream OpenFile(string path) => Assembly.GetManifestResourceStream(path);
+
+        /// <inheritdoc />
+        public IEnumerable<MappedResourceInfo> GetDirectoryEntries(string path, IMimeTypeProvider mimeTypeProvider)
+            => Enumerable.Empty<MappedResourceInfo>();
+    }
+}