Unset delegation propery from source queue. This removes the process from the target URL group and allows the delegation rule to be added back later on in the processes lifetime

Author: NGloreous

src/Servers/HttpSys/src/DelegationRule.cs

@@ -13,6 +13,7 @@ namespace Microsoft.AspNetCore.Server.HttpSys
     public class DelegationRule : IDisposable
     {
         private readonly ILogger _logger;
+        private readonly UrlGroup _sourceQueueUrlGroup;
         /// <summary>
         /// The name of the Http.Sys request queue
         /// </summary>
@@ -23,8 +24,9 @@ public class DelegationRule : IDisposable
         public string UrlPrefix { get; }
         internal RequestQueue Queue { get; }
 
-        internal DelegationRule(string queueName, string urlPrefix, ILogger logger)
+        internal DelegationRule(UrlGroup sourceQueueUrlGroup, string queueName, string urlPrefix, ILogger logger)
         {
+            _sourceQueueUrlGroup = sourceQueueUrlGroup;
             _logger = logger;
             QueueName = queueName;
             UrlPrefix = urlPrefix;
@@ -34,6 +36,7 @@ internal DelegationRule(string queueName, string urlPrefix, ILogger logger)
         /// <inheritdoc />
         public void Dispose()
         {
+            _sourceQueueUrlGroup.UnSetDelegationProperty(Queue, throwOnError: false);
             Queue.UrlGroup?.Dispose();
             Queue?.Dispose();
         }

src/Servers/HttpSys/src/NativeInterop/UrlGroup.cs

@@ -80,6 +80,15 @@ internal unsafe void SetDelegationProperty(RequestQueue destination)
             SetProperty(HttpApiTypes.HTTP_SERVER_PROPERTY.HttpServerDelegationProperty, new IntPtr(&propertyInfo), (uint)RequestPropertyInfoSize);
         }
 
+        internal unsafe void UnSetDelegationProperty(RequestQueue destination, bool throwOnError = true)
+        {
+            var propertyInfo = new HttpApiTypes.HTTP_BINDING_INFO();
+            propertyInfo.Flags = HttpApiTypes.HTTP_FLAGS.NONE;
+            propertyInfo.RequestQueueHandle = destination.Handle.DangerousGetHandle();
+
+            SetProperty(HttpApiTypes.HTTP_SERVER_PROPERTY.HttpServerDelegationProperty, new IntPtr(&propertyInfo), (uint)RequestPropertyInfoSize, throwOnError);
+        }
+
         internal void SetProperty(HttpApiTypes.HTTP_SERVER_PROPERTY property, IntPtr info, uint infosize, bool throwOnError = true)
         {
             Debug.Assert(info != IntPtr.Zero, "SetUrlGroupProperty called with invalid pointer");

src/Servers/HttpSys/src/ServerDelegationPropertyFeature.cs

@@ -21,7 +21,7 @@ public ServerDelegationPropertyFeature(RequestQueue queue, ILogger logger)
 
         public DelegationRule CreateDelegationRule(string queueName, string uri)
         {
-            var rule = new DelegationRule(queueName, uri, _logger);
+            var rule = new DelegationRule(_queue.UrlGroup, queueName, uri, _logger);
             _queue.UrlGroup.SetDelegationProperty(rule.Queue);
             return rule;
         }