func (c *Client) Out() []byte {
	if c.out.Len() == 0 {
		return nil
	}
	return c.out.Bytes()
}
func (c *Client) Out() []byte {
	if c.out.Len() == 0 {
		return nil
	}
	return c.out.Bytes()
}
// Out returns the data to be sent to the server in the current step.