update cim-client-sdk/cim-flutter-sdk/README.md.

Signed-off-by: 杨杰 <5301327+smebclub@user.noreply.gitee.com>

cim-client-sdk/cim-flutter-sdk/README.md

@@ -1,18 +1,41 @@
 # cim_flutter_sdk
 
-A new Flutter plugin project.
+开源通讯库 [CIM](https://gitee.com/farsunset/cim) 的 flutter版本SDK
 
-## Getting Started
+## 如何使用
 
-This project is a starting point for a Flutter
-[plug-in package](https://flutter.dev/developing-packages/),
-a specialized package that includes platform-specific implementation code for
-Android and/or iOS.
 
-For help getting started with Flutter development, view the
-[online documentation](https://flutter.dev/docs), which offers tutorials,
-samples, guidance on mobile development, and a full API reference.
 
-The plugin project was generated without specifying the `--platforms` flag, no platforms are currently supported.
-To add platforms, run `flutter create -t plugin --platforms <platforms> .` in this directory.
-You can also find a detailed instruction on how to add platforms in the `pubspec.yaml` at https://flutter.dev/docs/development/packages-and-plugins/developing-packages#plugin-platforms.
+```
+import 'package:cim_flutter_sdk/cim_flutter_sdk.dart';
+...
+
+CIMSocket cimSocket;
+
+String Message = 'Unknown';
+
+cimSocket = await _cimFlutterSdkPlugin.connect(
+          '127.0.0.1', 23456, 16501516154949);
+      cimSocket.addListener(() {
+        print(cimSocket.model!.toProto3Json());
+        if (!mounted) return;
+
+        setState(() {
+          Message = cimSocket.model!.toProto3Json().toString();
+        });
+      });
+
+...
+
+    return MaterialApp(
+      home: Scaffold(
+        appBar: AppBar(
+          title: const Text('Plugin example app'),
+        ),
+        body: Center(
+          child: Text('Message is: $Message\n'),
+        ),
+      ),
+    );
+
+```