/// <summary>
        /// Gets messages sent per second
        /// </summary>
        public float GetMessagesSentPerSecond(double now)
        {
            if (m_previousWindow != null)
            {
                return(m_previousWindow.GetMessagesSentPerSecond(now));
            }

            // (in previous window)
            return((float)m_messagesSent / m_totalTimeSpan);
        }