diff --git a/lib/src/async_cache.dart b/lib/src/async_cache.dart
index 36dec01..53084ca 100644
--- a/lib/src/async_cache.dart
+++ b/lib/src/async_cache.dart
@@ -89,16 +89,14 @@
   }
 
   /// Removes any cached value.
-  Null invalidate() {
+  void invalidate() {
+    // TODO: This does not return a future, but probably should.
     _cachedValueFuture = null;
     // TODO: This does not await, but probably should.
     _cachedStreamSplitter?.close();
     _cachedStreamSplitter = null;
     _stale?.cancel();
     _stale = null;
-
-    // TODO: This does not return a future, but probably should.
-    return null;
   }
 
   void _startStaleTimer() {
diff --git a/test/stream_queue_test.dart b/test/stream_queue_test.dart
index 37dedb9..b4600e2 100644
--- a/test/stream_queue_test.dart
+++ b/test/stream_queue_test.dart
@@ -153,8 +153,8 @@
 
     test("multiple requests at the same time", () async {
       var events = new StreamQueue<int>(createStream());
-      var result = await Future.wait(
-          [events.next, events.next, events.next, events.next]);
+      var result = await Future
+          .wait([events.next, events.next, events.next, events.next]);
       expect(result, [1, 2, 3, 4]);
       await events.cancel();
     });