protected void OnTimedEvent(SMSProvider smsProvider)
        {
            string text       = $"Message {++messageCounter} received. ";
            var    smsMessage = new SMSMessage(Guid.NewGuid(), _phoneNumber, text, DateTime.Now, smsProvider);

            RaiseSMSReceivedEvent(this, smsMessage);
        }
        private void RaiseSMSReceivedEvent(SMSProvider smsProvider, SMSMessage smsMessage)
        {
            var handler = SMSReceived;

            if (handler != null)
            {
                handler(smsProvider, smsMessage);
            }
        }