diff --git a/pkgs/async/lib/src/subscription_stream.dart b/pkgs/async/lib/src/subscription_stream.dart
index 96a7a2b1..e6630721 100644
--- a/pkgs/async/lib/src/subscription_stream.dart
+++ b/pkgs/async/lib/src/subscription_stream.dart
@@ -85,7 +85,3 @@ class _CancelOnErrorSubscriptionWrapper<T>
     });
   }
 }
-
-abstract class BinaryWrapper {
-  void binaryCall<T1, T2>(T1 t1, T2 t2);
-}