/// <summary>
        /// [Basic] 無視ユーザーリストを取得する
        /// </summary>
        /// <returns></returns>
        public async Task <IEnumerable <string> > GetIgnoreUsersAsync()
        {
            await CheckRk();

            var url      = $"{BaseUrl}/{Auth.UserName}/ignore.json?{DateTime.Now.Ticks}";
            var response = await GetJsonObjectAsync <IgnoreUsers>(url, GetCookieHeader());

            var result = response.Users.Select(x => x.Where(p => p.Key == "name").Select(p => p.Value).First());

            foreach (var u in result)
            {
                IgnoreUsersSet.Add(u);
            }

            return(result);
        }
        /// <summary>
        /// [Basic] 対象ユーザーを無視ユーザーリストに追加する
        /// </summary>
        /// <param name="userName"></param>
        /// <returns></returns>
        public async Task IgnoreUserAsync(string userName)
        {
            if (string.IsNullOrWhiteSpace(userName))
            {
                throw new ArgumentException("username is empty", nameof(userName));
            }

            await CheckRk();

            var url  = $"{BaseUrl}/{Auth.UserName}/api.ignore";
            var data = new Dictionary <string, string>
            {
                { "rks", RksForBookmark },
                { "username", userName }
            };

            await PostAsync(url, data, GetCookieHeader());

            IgnoreUsersSet.Add(userName);
        }