for k := range m {
		keys = append(keys, k)
	}
	sort.Strings(keys)
	for _, k := range keys {
		v := m[k]
		keyEscaped := url.QueryEscape(k)
		if buf.Len() > 1 {
			buf.WriteByte('&')
		}
		buf.WriteString(keyEscaped)
		buf.WriteByte('=')
		buf.WriteString(url.QueryEscape(v))
	}
	return buf.String()
}

// NewBytes returns a new Bytes.
// A slice is preallocated.
func NewBytes() *Bytes {