/// <summary>
        /// To save the board.
        /// </summary>
        /// <param name="board">Trading board.</param>
        public virtual void Save(ExchangeBoard board)
        {
            if (board == null)
            {
                throw new ArgumentNullException(nameof(board));
            }

            lock (_boards.SyncRoot)
            {
                if (!_boards.TryAdd(board.Code, board))
                {
                    return;
                }
            }

            BoardAdded?.Invoke(board);
        }
        /// <summary>
        /// To save the board.
        /// </summary>
        /// <param name="board">Trading board.</param>
        public virtual void Save(ExchangeBoard board)
        {
            if (board == null)
            {
                throw new ArgumentNullException(nameof(board));
            }

            lock (_boards.SyncRoot)
            {
                var oldBoard = _boards.TryGetValue(board.Code);

                if (ReferenceEquals(oldBoard, board))
                {
                    return;
                }

                _boards[board.Code] = board;
            }

            BoardAdded?.Invoke(board);
        }