diff --git a/Source/Orleankka.Runtime/InvokeMethodRequestExtensions.cs b/Source/Orleankka.Runtime/InvokeMethodRequestExtensions.cs
index 255f6e4c..ba0614ad 100644
--- a/Source/Orleankka.Runtime/InvokeMethodRequestExtensions.cs
+++ b/Source/Orleankka.Runtime/InvokeMethodRequestExtensions.cs
@@ -1,5 +1,4 @@
 using System;
-using System.Linq;
 
 using Orleans.CodeGeneration;
 using Orleans.Concurrency;
@@ -8,13 +7,8 @@ namespace Orleankka
 {
     public static class InvokeMethodRequestExtensions
     {
-        public static bool Any(this InvokeMethodRequest request, params Type[] messages)
-        {
-            var message = request.Message().GetType();
-            return messages.Any(x => x == message);
-        }
-
-        public static T Message<T>(this InvokeMethodRequest request) => (T) request.Message();
+        public static bool Message(this InvokeMethodRequest request, Func<object, bool> predicate) => 
+            predicate(request.Message());
 
         public static object Message(this InvokeMethodRequest request)
         {
@@ -30,6 +24,6 @@ public static object Message(this InvokeMethodRequest request)
         }
 
         static object UnwrapImmutable(object item) => 
-            item is Immutable<object> ? ((Immutable<object>)item).Value : item;
+            item is Immutable<object> immutable ? immutable.Value : item;
     }
 }
\ No newline at end of file
diff --git a/Tests/Orleankka.Tests/Features/Reentrant_messages.cs b/Tests/Orleankka.Tests/Features/Reentrant_messages.cs
index f16681c3..35a089b0 100644
--- a/Tests/Orleankka.Tests/Features/Reentrant_messages.cs
+++ b/Tests/Orleankka.Tests/Features/Reentrant_messages.cs
@@ -75,9 +75,8 @@ public interface ITestReentrantStreamConsumerActor : IActorGrain
         [MayInterleave(nameof(Interleave))]
         public class TestReentrantStreamConsumerActor : DispatchActorGrain, ITestReentrantStreamConsumerActor
         {
-            public static bool Interleave(InvokeMethodRequest req) => req.Any(
-                typeof(GetStreamMessagesInProgress), 
-                typeof(int)); // 1-st stream message type
+            public static bool Interleave(InvokeMethodRequest req) => 
+                req.Message(x => x is GetStreamMessagesInProgress || x is int); // int is 1-st stream message type
 
             readonly List<object> streamMessagesInProgress = new List<object>();
             List<object> On(GetStreamMessagesInProgress x) => streamMessagesInProgress;