Overload ReassignProxyRequest to also accept a route update

src/ReverseProxy/Model/HttpContextFeaturesExtensions.cs

@@ -60,4 +60,24 @@ public static void ReassignProxyRequest(this HttpContext context, ClusterState c
         };
         context.Features.Set<IReverseProxyFeature>(newFeature);
     }
+
+    // ReassignProxyRequest overload to also replace the route when updating IReverseProxyFeature
+    /// <summary>
+    /// Replaces the assigned route, cluster, and destinations in <see cref="IReverseProxyFeature"/> with the new <see cref="RouteModel"/>
+    /// and new <see cref="ClusterState"/>, causing the request to be sent using the new route to the new cluster.
+    /// </summary>
+    public static void ReassignProxyRequest(this HttpContext context, RouteModel route, ClusterState cluster)
+    {
+        var oldFeature = context.GetReverseProxyFeature();
+        var destinations = cluster.DestinationsState;
+        var newFeature = new ReverseProxyFeature()
+        {
+            Route = route,
+            Cluster = cluster.Model,
+            AllDestinations = destinations.AllDestinations,
+            AvailableDestinations = destinations.AvailableDestinations,
+            ProxiedDestination = oldFeature.ProxiedDestination,
+        };
+        context.Features.Set<IReverseProxyFeature>(newFeature);
+    }
 }

test/ReverseProxy.Tests/Model/HttpContextFeaturesExtensions.cs

@@ -49,5 +49,17 @@ public void ReassignProxyRequest_Success()
         Assert.Same(d1, newFeature.ProxiedDestination); // Copied unmodified.
         Assert.Same(cm2, newFeature.Cluster);
         Assert.Same(r1, newFeature.Route);
+
+        // Begin testing ReassignProxyRequest(route, cluster) overload
+        var r2 = new RouteModel(new RouteConfig() { RouteId = "r2" }, cs2, HttpTransformer.Empty);
+        context.ReassignProxyRequest(r2, cs2);
+
+        var newFeatureOverload = context.GetReverseProxyFeature();
+        Assert.NotSame(newFeature, newFeatureOverload);
+        Assert.Same(d2, newFeatureOverload.AllDestinations); // Unmodified
+        Assert.Same(d2, newFeatureOverload.AvailableDestinations); // Unmodified
+        Assert.Same(d1, newFeatureOverload.ProxiedDestination); // Unmodified
+        Assert.Same(cm2, newFeatureOverload.Cluster); // Unmodified
+        Assert.Same(r2, newFeatureOverload.Route); // Asset route update
     }
 }