public bool OnSendCompleted(int bytesTransferred)
{
_totalAmountToSend -= bytesTransferred;
_bytesToSend -= bytesTransferred;
_offset += bytesTransferred;
if (_bytesToSend <= 0)
_offset = 0;
if (_totalAmountToSend == 0)
{
Clear();
}
return _totalAmountToSend <= 0;
}