void RequestLastBlock(EndPoint address = null)
        {
            var message = new RequestBlocksMessage(new List <string>());

            if (address != null)
            {
                net.SendMessageToPeer(message, address);
            }
            else
            {
                net.SendMessageToAllPeers(message);
            }
        }
        public void RequestBlock(string hash, EndPoint peerAddress = null)
        {
            var list = new List <string>();

            list.Add(hash);
            var message = new RequestBlocksMessage(list);

            if (peerAddress == null)
            {
                net.SendMessageToAllPeers(message);
            }
            else
            {
                net.SendMessageToPeer(message, peerAddress);
            }
        }