/// Transfer data to server in blocks
/// </summary>
/// <returns>true if there are more blocks to be transferred</returns>
private static void TransferToServerInBlocks()
{
CoAPRequest blockPUTReq = new CoAPRequest(CoAPMessageType.CON, CoAPMessageCode.PUT, coapClient.GetNextMessageID());
blockPUTReq.SetURL("coap://localhost:5683/largedata/blockput");
blockPUTReq.AddTokenValue(DateTime.Today.ToString("HHmm"));
//Get needed bytes from source
int copyBeginIdx = (int)(_blockSeqNo * BLOCK_SIZE_BYTES);
int bytesToCopy = ((copyBeginIdx + BLOCK_SIZE_BYTES) < _dataToTransfer.Length) ? BLOCK_SIZE_BYTES : (_dataToTransfer.Length - copyBeginIdx);
byte[] blockToSend = new byte[bytesToCopy];
Array.Copy(_dataToTransfer, copyBeginIdx, blockToSend, 0, bytesToCopy);
//Calculate how many more bytes left to transfer
bool hasMore = (_totalBytesTransferred + bytesToCopy < _dataToTransfer.Length);
//Add the bytes to the payload
blockPUTReq.Payload = new CoAPPayload(blockToSend);
//Now add block option to the request
blockPUTReq.SetBlockOption(CoAPHeaderOption.BLOCK1, new CoAPBlockOption(_blockSeqNo, hasMore, CoAPBlockOption.BLOCK_SIZE_16));
//send
coapClient.Send(blockPUTReq);
//Updated bytes transferred
_totalBytesTransferred += bytesToCopy;
}