sub.go
func (c Sub) Write(w *bufio.Writer) (err error) {
	for _, s := range [...]string{
		"SUB ",
		c.Topic,
		" ",
		c.Channel,
		"\n",
	} {
		if _, err = w.WriteString(s); err != nil {
			err = errors.Wrap(err, "writing SUB command")
			return
		}
	}
	return
}
func (c Sub) Write(w *bufio.Writer) (err error) {
	for _, s := range [...]string{
		"SUB ",
		c.Topic,
		" ",
		c.Channel,
		"\n",
	} {
		if _, err = w.WriteString(s); err != nil {
			err = errors.Wrap(err, "writing SUB command")
			return
		}
	}
	return
}
// Write serializes the command to the given buffered output, satisfies the
// Command interface.