listener remove future

.idea/workspace.xml

@@ -3,10 +3,7 @@
   <component name="ChangeListManager">
     <list default="true" id="2f8e3712-04e2-429a-bcea-c8db1a54008e" name="默认变更列表" comment="">
       <change beforePath="$PROJECT_DIR$/.idea/workspace.xml" beforeDir="false" afterPath="$PROJECT_DIR$/.idea/workspace.xml" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/example/lib/main.dart" beforeDir="false" afterPath="$PROJECT_DIR$/example/lib/main.dart" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/example/pubspec.lock" beforeDir="false" afterPath="$PROJECT_DIR$/example/pubspec.lock" afterDir="false" />
       <change beforePath="$PROJECT_DIR$/lib/dj_printer.dart" beforeDir="false" afterPath="$PROJECT_DIR$/lib/dj_printer.dart" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/pubspec.lock" beforeDir="false" afterPath="$PROJECT_DIR$/pubspec.lock" afterDir="false" />
     </list>
     <option name="SHOW_DIALOG" value="false" />
     <option name="HIGHLIGHT_CONFLICTS" value="true" />
@@ -51,6 +48,7 @@
   </component>
   <component name="PropertiesComponent">
     <property name="dart.analysis.tool.window.force.activate" value="true" />
+    <property name="dart.analysis.tool.window.visible" value="false" />
     <property name="io.flutter.reload.alreadyRun" value="true" />
     <property name="last_opened_file_path" value="$PROJECT_DIR$" />
     <property name="settings.editor.selected.configurable" value="flutter.settings" />

lib/dj_printer.dart

@@ -14,10 +14,10 @@ class DjPrinter {
       EventChannel("com.discovery.devices");
   StreamSubscription? _discoveryStream;
 
-  Future<StreamSubscription> addDiscoveryListen(
+  StreamSubscription addDiscoveryListen(
       {required void Function(dynamic data) onReceive,
       void Function()? onStart,
-      void Function()? onFinish}) async {
+      void Function()? onFinish}) {
     if (_discoveryStream == null) {
       return _deviceChannel.receiveBroadcastStream().listen((data) {
         if (data == "start" && onStart != null) {
@@ -43,9 +43,9 @@ class DjPrinter {
   static const EventChannel _connectChannel = EventChannel("com.connect");
   StreamSubscription? _connectStream;
 
-  Future<StreamSubscription> addConnectListen(
+  StreamSubscription addConnectListen(
       {required void Function() onConnect,
-      required void Function() onDisconnect}) async {
+      required void Function() onDisconnect}) {
     if (_connectStream == null) {
       return _connectChannel.receiveBroadcastStream().listen((data) {
         if (data == 'connected') {