private void Encode(bool flush)
{
var bytesNeeded = _encoder.GetByteCount(
_textArray,
_textBegin,
_textEnd - _textBegin,
flush);
Grow(bytesNeeded);
var bytesUsed = _encoder.GetBytes(
_textArray,
_textBegin,
_textEnd - _textBegin,
_dataArray,
_dataEnd,
flush);
_textBegin = _textEnd = 0;
_dataEnd += bytesUsed;
}