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/Net/Internal/WebSocketHandshakeResponse.cs

@@ -0,0 +1,53 @@
+using System;
+using System.Collections.Specialized;
+using System.Globalization;
+using System.Net;
+using System.Text;
+
+namespace EmbedIO.Net.Internal
+{
+    internal class WebSocketHandshakeResponse
+    {
+        private const int HandshakeStatusCode = (int)HttpStatusCode.SwitchingProtocols;
+
+        internal WebSocketHandshakeResponse(IHttpContext context)
+        {
+            ProtocolVersion = HttpVersion.Version11;
+            Headers = context.Response.Headers;
+            Headers.Clear(); // Use only headers mentioned in RFC6455 - scrap all the rest.
+            StatusCode = HandshakeStatusCode;
+            Reason = HttpListenerResponseHelper.GetStatusDescription(HandshakeStatusCode);
+
+            Headers[HttpHeaderNames.Upgrade] = "websocket";
+            Headers[HttpHeaderNames.Connection] = "Upgrade";
+
+            foreach (var cookie in context.Request.Cookies)
+            {
+                Headers.Add("Set-Cookie", cookie.ToString());
+            }
+        }
+
+        public string Reason { get; }
+
+        public int StatusCode { get; }
+        
+        public NameValueCollection Headers { get; }
+
+        public Version ProtocolVersion { get; }
+
+        public override string ToString()
+        {
+            var output = new StringBuilder(64)
+                .AppendFormat(CultureInfo.InvariantCulture, "HTTP/{0} {1} {2}\r\n", ProtocolVersion, StatusCode, Reason);
+
+            foreach (var key in Headers.AllKeys)
+            {
+                _ = output.AppendFormat(CultureInfo.InvariantCulture, "{0}: {1}\r\n", key, Headers[key]);
+            }
+
+            _ = output.Append("\r\n");
+            
+            return output.ToString();
+        }
+    }
+}