检查好友关系

OpenIMClient.getInstance().friendshipManager.checkFriend(
    new OnBase<List<FriendshipInfo>>() {
        @Override
        public void onSuccess(List<FriendshipInfo> relations) {
            showFriendshipStates(relations);
        }

        @Override
        public void onError(int code, String error) {
            recordFriendshipCheckFailure(code, error);
        }
    },
    Arrays.asList("user_a", "user_b")
);