init method

@override void init()

初始化，建议在登录之前调用，IMKitClient会自动调用

Implementation

@override
void init() {
  onContactListComplete = _onContactListComplete.stream;
  subscriptions.add(NimCore.instance.loginService.onDataSync.listen((event) {
    if (event.type == NIMDataSyncType.nimDataSyncMain &&
        event.state == NIMDataSyncState.nimDataSyncStateCompleted) {
      fetchContactList();
    }
  }));
  initListener();
}