/// <summary>
        /// For clients
        /// </summary>
        /// <returns></returns>
        public static Velocimeter getInstance()
        {
            if (instance == null)
            {
                instance = new Velocimeter();
            }

            return(instance);
        }
        /// <summary>
        /// for senders
        /// </summary>
        /// <param name="totalMessages"></param>
        /// <returns></returns>
        public static Velocimeter getInstance(int totalMessages)
        {
            if (instance == null)
            {
                instance = new Velocimeter(totalMessages);
            }

            return(instance);
        }