/// <summary> Called to return the PDU for this type of object </summary>
/// <returns> byte[] </returns>
public byte[] GetPDU()
{
SmppBuffer tmpBuff = new SmppBuffer(DefaultEncoding, this);
tmpBuff.AddCString(MessageId);
tmpBuff.AddUnsuccessDestinationAddresses(UnsuccessDestinationAddresses);
if (Optional.Count > 0)
{
tmpBuff.AddTLVCollection(Optional);
}
tmpBuff.AddFinalLength();
return tmpBuff.Buffer;
}