Enforce and fix prefer_typting_uninitialized_variables

pkgs/stream_transform/analysis_options.yaml

diff --git a/pkgs/stream_transform/analysis_options.yaml b/pkgs/stream_transform/analysis_options.yaml
index 906ceb0..9d680af 100644
--- a/pkgs/stream_transform/analysis_options.yaml
+++ b/pkgs/stream_transform/analysis_options.yaml
@@ -69,7 +69,7 @@
     - prefer_is_not_empty
     - prefer_null_aware_operators
     - prefer_single_quotes
-    #- prefer_typing_uninitialized_variables
+    - prefer_typing_uninitialized_variables
     - recursive_getters
     - slash_for_doc_comments
     - test_types_in_equals

pkgs/stream_transform/test/tap_test.dart

diff --git a/pkgs/stream_transform/test/tap_test.dart b/pkgs/stream_transform/test/tap_test.dart
index 989c342..3b52442 100644
--- a/pkgs/stream_transform/test/tap_test.dart
+++ b/pkgs/stream_transform/test/tap_test.dart
@@ -23,7 +23,7 @@
   });
 
   test('calls function for errors', () async {
-    var error;
+    dynamic error;
     var source = StreamController();
     source.stream
         .transform(tap((_) {}, onError: (e, st) {
@@ -36,7 +36,7 @@
   });
 
   test('forwards errors', () async {
-    var error;
+    dynamic error;
     var source = StreamController();
     source.stream.transform(tap((_) {}, onError: (e, st) {})).listen((_) {},
         onError: (e) {