Fix deprecated zone API usage (#95)

diff --git a/.travis.yml b/.travis.yml
index a3bc070..2c6dc5a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,7 +2,7 @@
 
 dart:
 - dev
-- 2.2.0
+- 2.8.4
 
 os:
 - linux
@@ -16,7 +16,7 @@
   include:
   - dart: dev
     dart_task: dartfmt
-  - dart: 2.2.0
+  - dart: 2.8.4
     dart_task:
       dartanalyzer: --fatal-warnings .
   - dart: dev
diff --git a/CHANGELOG.md b/CHANGELOG.md
index a98ae20..881aa2f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,7 @@
-# 0.9.8
+# 0.9.8-dev
 
 * Add the ability to create custom Watcher types for specific file paths.
+* Require at least Dart 2.8.4.
 
 # 0.9.7+15
 
diff --git a/lib/src/directory_watcher/windows.dart b/lib/src/directory_watcher/windows.dart
index f5093c5..ae4670d 100644
--- a/lib/src/directory_watcher/windows.dart
+++ b/lib/src/directory_watcher/windows.dart
@@ -379,11 +379,11 @@
   void _startWatch() {
     // Note: "watcher closed" exceptions do not get sent over the stream
     // returned by watch, and must be caught via a zone handler.
-    runZoned(() {
+    runZonedGuarded(() {
       var innerStream = Directory(path).watch(recursive: true);
       _watchSubscription = innerStream.listen(_onEvent,
           onError: _eventsController.addError, onDone: _onDone);
-    }, onError: (error, StackTrace stackTrace) {
+    }, (error, StackTrace stackTrace) {
       if (error is FileSystemException &&
           error.message.startsWith('Directory watcher closed unexpectedly')) {
         _watchSubscription.cancel();
diff --git a/pubspec.yaml b/pubspec.yaml
index e86192d..c4cafad 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,13 +1,13 @@
 name: watcher
-version: 0.9.7+15
+version: 0.9.8-dev
 
 description: >-
   A file system watcher. It monitors changes to contents of directories and
   sends notifications when files have been added, removed, or modified.
-homepage: https://github.com/dart-lang/watcher
+repository: https://github.com/dart-lang/watcher
 
 environment:
-  sdk: '>=2.2.0 <3.0.0'
+  sdk: '>=2.8.4 <3.0.0'
 
 dependencies:
   async: ^2.0.0