public Task Add(IEnumerable <SmsMessage> messages, CancellationToken token = default(CancellationToken))
        {
            foreach (var message in messages)
            {
                _db.SmsMessages.Add(message);
            }

            return(_db.SaveChangesAsync(token));
        }
        public async Task Prefill(CallsRegistryContext dbContext)
        {
            if (await dbContext.PhoneCalls.AnyAsync())
            {
                return;
            }

            var msisdn = GenerateMSISDN().ToList();

            await dbContext.PhoneCalls.AddRangeAsync(GenerateCalls(msisdn));

            await dbContext.SmsMessages.AddRangeAsync(GenerateSmsMessages(msisdn));

            await dbContext.SaveChangesAsync();
        }