// insignificant space characters elided.
func Compact(dst *bytes.Buffer, src []byte) error {
	dst.Grow(len(src))
	b := dst.AvailableBuffer()
	b, err := appendCompact(b, src, false)
	dst.Write(b)
	return err
}

func appendCompact(dst, src []byte, escape bool) ([]byte, error) {
	origLen := len(dst)
	scan := newScanner()
	defer freeScanner(scan)
	start := 0
	for i, c := range src {