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/IHttpContextImpl.cs

@@ -0,0 +1,88 @@
+using System;
+using System.Collections.Generic;
+using System.Security.Principal;
+using System.Threading;
+using System.Threading.Tasks;
+using EmbedIO.Routing;
+using EmbedIO.Sessions;
+using EmbedIO.Utilities;
+using EmbedIO.WebSockets;
+
+namespace EmbedIO
+{
+    /// <summary>
+    /// <para>Represents a HTTP context implementation, i.e. a HTTP context as seen internally by EmbedIO.</para>
+    /// <para>This API mainly supports the EmbedIO infrastructure; it is not intended to be used directly from your code,
+    /// unless to address specific needs in the implementation of EmbedIO plug-ins (e.g. modules).</para>
+    /// </summary>
+    /// <seealso cref="IHttpContext" />
+    public interface IHttpContextImpl : IHttpContext
+    {
+        /// <summary>
+        /// <para>Gets or sets a <see cref="CancellationToken" /> used to stop processing of this context.</para>
+        /// <para>This API supports the EmbedIO infrastructure and is not intended to be used directly from your code.</para>
+        /// </summary>
+        new CancellationToken CancellationToken { get; set; }
+
+        /// <summary>
+        /// Gets or sets the route matched by the requested URL path.
+        /// </summary>
+        new RouteMatch Route { get; set; }
+
+        /// <summary>
+        /// <para>Gets or sets the session proxy associated with this context.</para>
+        /// <para>This API supports the EmbedIO infrastructure and is not intended to be used directly from your code.</para>
+        /// </summary>
+        /// <value>
+        /// An <see cref="ISessionProxy"/> interface.
+        /// </value>
+        new ISessionProxy Session { get; set; }
+
+        /// <summary>
+        /// <para>Gets or sets the user.</para>
+        /// <para>This API supports the EmbedIO infrastructure and is not intended to be used directly from your code.</para>
+        /// </summary>
+        new IPrincipal User { get; set; }
+
+        /// <summary>
+        /// <para>Gets or sets a value indicating whether compressed request bodies are supported.</para>
+        /// <para>This API supports the EmbedIO infrastructure and is not intended to be used directly from your code.</para>
+        /// </summary>
+        /// <seealso cref="WebServerOptionsBase.SupportCompressedRequests"/>
+        new bool SupportCompressedRequests { get; set; }
+
+        /// <summary>
+        /// <para>Gets the MIME type providers.</para>
+        /// <para>This API supports the EmbedIO infrastructure and is not intended to be used directly from your code.</para>
+        /// </summary>
+        MimeTypeProviderStack MimeTypeProviders { get; }
+
+        /// <summary>
+        /// <para>Flushes and closes the response stream, then calls any registered close callbacks.</para>
+        /// <para>This API supports the EmbedIO infrastructure and is not intended to be used directly from your code.</para>
+        /// </summary>
+        /// <seealso cref="IHttpContext.OnClose"/>
+        void Close();
+
+        /// <summary>
+        /// <para>Asynchronously handles a WebSockets opening handshake
+        /// and returns a newly-created <seealso cref="IWebSocketContext"/> interface.</para>
+        /// <para>This API supports the EmbedIO infrastructure and is not intended to be used directly from your code.</para>
+        /// </summary>
+        /// <param name="requestedProtocols">The requested WebSocket sub-protocols.</param>
+        /// <param name="acceptedProtocol">The accepted WebSocket sub-protocol,
+        /// or the empty string is no sub-protocol has been agreed upon.</param>
+        /// <param name="receiveBufferSize">Size of the receive buffer.</param>
+        /// <param name="keepAliveInterval">The keep-alive interval.</param>
+        /// <param name="cancellationToken">A <see cref="CancellationToken"/> used to stop the server.</param>
+        /// <returns>
+        /// An <see cref="IWebSocketContext"/> interface.
+        /// </returns>
+        Task<IWebSocketContext> AcceptWebSocketAsync(
+            IEnumerable<string> requestedProtocols, 
+            string acceptedProtocol, 
+            int receiveBufferSize, 
+            TimeSpan keepAliveInterval,
+            CancellationToken cancellationToken);
+    }
+}