public void synchronizationRemote() {
   friendshipResource
       .list()
       .observeOn(Schedulers.io())
       .subscribeOn(Schedulers.io())
       .flatMap(list -> Observable.from(list))
       .subscribe(
           friendVo -> {
             Friend friend =
                 friendDao.queryBuilder().where(FriendDao.Properties.Uid.eq(friendVo.id)).unique();
             if (friend == null) {
               friend = new Friend();
               friend.setUid(friendVo.id);
               friend.setUsername(friendVo.username);
               friend.setNickname(friendVo.nickname);
               friend.setAvatar(friendVo.avatar);
             } else {
               friend.setUsername(friendVo.username);
               friend.setNickname(friendVo.nickname);
               friend.setAvatar(friendVo.avatar);
             }
             friendDao.insertOrReplace(friend);
           });
 }