public async Task RemoveBySubject(string subject)
        {
            if (subject == null)
            {
                throw new ArgumentNullException(nameof(subject));
            }

            using (var c = await RedisManager.GetConnection())
            {
                var skKey = SubjectRefreshTokensRedisKey.Create(subject);
                var sk    = new RedisKey <SubjectRefreshTokenList>(skKey, c);
                var subjectRefreshTokenList = await sk.GetAsync();

                if (subjectRefreshTokenList != null)
                {
                    var keysToRemove = subjectRefreshTokenList
                                       .Select(itm => RefreshTokenRedisKey.Create(itm.RefreshToken));
                    await c.DeleteKeysAsync(keysToRemove);
                }

                await sk.DeleteAsync();
            }
        }