diff --git a/lib/src/decoder.dart b/lib/src/decoder.dart
index b3d8281..4f14496 100644
--- a/lib/src/decoder.dart
+++ b/lib/src/decoder.dart
@@ -5,7 +5,7 @@ import "dart:convert";
 
 import "event.dart";
 
-typedef void RetryIndicator(Duration);
+typedef RetryIndicator = void Function(Duration retry);
 
 class EventSourceDecoder implements StreamTransformer<List<int>, Event> {
   RetryIndicator retryIndicator;