Change other futures to also have timeout take a named parameter.

pkg/scheduled_test/lib/src/substitute_future.dart

Index: pkg/scheduled_test/lib/src/substitute_future.dart
diff --git a/pkg/scheduled_test/lib/src/substitute_future.dart b/pkg/scheduled_test/lib/src/substitute_future.dart
index d30c9364e886ac4660eab75713b6be93cd90b59c..5c916895a883fe3d4246949cf24a261d7bb865c9 100644
--- a/pkg/scheduled_test/lib/src/substitute_future.dart
+++ b/pkg/scheduled_test/lib/src/substitute_future.dart
@@ -29,8 +29,8 @@ class SubstituteFuture<T> implements Future<T> {
   Future then(onValue(T value), {Function onError}) =>
     _completer.future.then(onValue, onError: onError);
   Future<T> whenComplete(action()) => _completer.future.whenComplete(action);
-  Future timeout(Duration timeLimit, [void onTimeout()]) =>
-    _completer.future.timeout(timeLimit, onTimeout);
+  Future timeout(Duration timeLimit, {void onTimeout()}) =>
+    _completer.future.timeout(timeLimit, onTimeout: onTimeout);
 
   /// Substitutes [newFuture] for the currently wrapped [Future], which is
   /// returned.