func NewReaderSize(r io.Reader, size int) *Reader {
	return &Reader{
		rd: bufio.NewReaderSize(r, size),
		tr: unicode.Cesu8ToUtf8Transformer,
	}
}
func NewReaderSize(r io.Reader, size int) *Reader {
	return &Reader{
		rd: bufio.NewReaderSize(r, size),
		tr: unicode.Cesu8ToUtf8Transformer,
	}
}
// NewReaderSize creates a new Reader instance with given size for bufio.Reader.