internal/bufio/bufio.go
func NewWriterSize(w io.Writer, size int) *Writer {
	return &Writer{
		wr: bufio.NewWriterSize(w, size),
		b:  make([]byte, writerBufferSize),
		tr: unicode.Utf8ToCesu8Transformer,
	}
}
func NewWriterSize(w io.Writer, size int) *Writer {
	return &Writer{
		wr: bufio.NewWriterSize(w, size),
		b:  make([]byte, writerBufferSize),
		tr: unicode.Utf8ToCesu8Transformer,
	}
}
// NewWriterSize creates a new Writer instance with given size for bufio.Writer.