Thank you so much for your answer. I necessarily use your answer in my next projects. But for now, I wrote packet queuing byt myself. There is my solution if your interested:

1. When receive handler executing, I’m using
PacketHeader.GetOption(PacketHeaderLongItems.PacketSequenceNumber)
2. If this packet number is greater then the last number more than 1 (first packet number is 2, because, I think, that the real first packet is “NULL” packet), this packet is queuing and executing later.

Packet queuing:

private Dictionary<long, int[]> queuedData;
lock (queuedData)
{
  queuedData.Add(packetNo, data);
  WriteLog(String.Format("Received packet No {0}. Data: {1} {2} {3}.
  Queued.", packetNo,
  data[0].ToString("X8"),
  data[1].ToString("X8"),
  data[2].ToString("X8")));
}

3. Queued data is processing by the special thread, running in background all the time, while connection is alive. Queued data is processing 1 time in 100 millisecond. Here the code:

void FindAndProcessQueuedPackets()
        {
            try
            {
                while (true)
                {
                    bool isDone = false;
                    while (!isDone)
                    {
                        bool isFound = false;
                        for (int i = 0; i < queuedData.Count; i++)
                        {                            
                            lock (queuedData)
                            {
                                if (queuedData.Keys.ElementAt(i) == lastPacketNo + 1)
                                {
                                    isFound = true;
                                    int[] queuedPacketData = queuedData.Values.ElementAt(i);

                                    WriteLog(String.Format("Processing queued packet No {0}. Data: {1} {2} {3}.",
                                                                                                      queuedData.Keys.ElementAt(i),
                                                                                                      queuedPacketData[0].ToString("X8"),
                                                                                                      queuedPacketData[1].ToString("X8"),
                                                                                                      queuedPacketData[2].ToString("X8")));

                                    NETWORK_MESSAGE queuedMessage = (NETWORK_MESSAGE)queuedPacketData[0];
                                    int queuedParameter1 = queuedPacketData[1];
                                    int queuedParameter2 = queuedPacketData[2];

                                    switch (queuedMessage)
                                    {
                                        case NETWORK_MESSAGE.HELLO:
                                            {
                                                if (isServer)
                                                    SendMessage(NETWORK_MESSAGE.HELLO);
                                                break;
                                            }
                                    }

                                    queuedData.Remove(queuedData.Keys.ElementAt(i));
                                    lastPacketNo++;
                                    MessageReceivedEvent(this, new NetworkMessageEventArgs(queuedMessage, queuedParameter1, queuedParameter2));
                                }                                
                            }
                        }
                        if (!isFound)
                            isDone = true;
                    }
                    Thread.Sleep(100);
                }
            }
            catch (ThreadAbortException ex)
            {
                ;
            }
        }

And, thank you so much for this library. It’s awesome! ) It’s very useful and easy to include in the projects. Please, don’t stop in development of this library. Thank you, and sorry for my bad english.