如何在Flutter中用Agora实现Callkeep？

dependencies:
  agora_rtc_engine: ^4.0.0

import 'package:agora_rtc_engine/rtc_engine.dart';
import 'package:agora_rtc_engine/rtc_local_view.dart' as RtcLocalView;
import 'package:agora_rtc_engine/rtc_remote_view.dart' as RtcRemoteView;

void initializeAgora() {
  RtcEngine.create('YOUR_APP_ID');
  RtcEngine.enableVideo();
  RtcEngine.setChannelProfile(ChannelProfile.Communication);
}

void startCall() async {
  await RtcEngine.joinChannel(null, 'channel_name', null, 0);
}

void endCall() async {
  await RtcEngine.leaveChannel();
}

void switchCamera() {
  RtcEngine.switchCamera();
}

Widget buildVideoView() {
  return Stack(
    children: [
      RtcLocalView.SurfaceView(),
      RtcRemoteView.SurfaceView(uid: remoteUid),
    ],
  );
}

dependencies:
  flutter_callkeep: ^2.0.0

import 'package:flutter_callkeep/flutter_callkeep.dart';

void main() {
  FlutterCallkeep.setup(<String, dynamic>{
    'ios': {
      'appName': 'Your App Name',
      'maximumCallGroups': '1',
      'maximumCallsPerCallGroup': '1',
    },
    'android': {
      'alertTitle': 'Permissions required',
      'alertDescription': 'This application needs to access your phone accounts',
      'cancelButton': 'Cancel',
      'okButton': 'OK',
    },
  });
  runApp(MyApp());
}

import 'package:flutter_callkeep/flutter_callkeep.dart';

void startCall() async {
  await FlutterCallkeep.startCall(
    uuid: 'call_uuid',
    number: 'callee_number',
    callerName: 'caller_name',
    handleType: 'number',
    hasVideo: true,
  );
}

void endCall() async {
  await FlutterCallkeep.endCall('call_uuid');
}