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/StringExtensions.cs

@@ -0,0 +1,77 @@
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace EmbedIO.Net.Internal
+{
+    internal static class StringExtensions
+    {
+        private const string TokenSpecialChars = "()<>@,;:\\\"/[]?={} \t";
+        
+        internal static bool IsToken(this string @this)
+            => @this.All(c => c >= 0x20 && c < 0x7f && TokenSpecialChars.IndexOf(c) < 0);
+
+        internal static IEnumerable<string> SplitHeaderValue(this string @this, bool useCookieSeparators)
+        {
+            var len = @this.Length;
+
+            var buff = new StringBuilder(32);
+            var escaped = false;
+            var quoted = false;
+
+            for (var i = 0; i < len; i++)
+            {
+                var c = @this[i];
+
+                if (c == '"')
+                {
+                    if (escaped)
+                    {
+                        escaped = false;
+                    }
+                    else
+                    {
+                        quoted = !quoted;
+                    }
+                }
+                else if (c == '\\')
+                {
+                    if (i < len - 1 && @this[i + 1] == '"')
+                    {
+                        escaped = true;
+                    }
+                }
+                else if (c == ',' || (useCookieSeparators && c == ';'))
+                {
+                    if (!quoted)
+                    {
+                        yield return buff.ToString();
+                        buff.Length = 0;
+
+                        continue;
+                    }
+                }
+
+                _ = buff.Append(c);
+            }
+
+            if (buff.Length > 0)
+            {
+                yield return buff.ToString();
+            }
+        }
+
+        internal static string Unquote(this string str)
+        {
+            var start = str.IndexOf('\"');
+            var end = str.LastIndexOf('\"');
+
+            if (start >= 0 && end >= 0)
+            {
+                str = str.Substring(start + 1, end - 1);
+            }
+
+            return str.Trim();
+        }
+    }
+}