xmpp.go
func (c *Client) SendHtml(chat Chat) (n int, err error) {
	return fmt.Fprintf(c.conn, "<message to='%s' type='%s' xml:lang='en'>"+
		"<body>%s</body>"+
		"<html xmlns='http://jabber.org/protocol/xhtml-im'><body xmlns='http://www.w3.org/1999/xhtml'>%s</body></html></message>",
		xmlEscape(chat.Remote), xmlEscape(chat.Type), xmlEscape(chat.Text), chat.Text)
}
func (c *Client) SendHtml(chat Chat) (n int, err error) {
	return fmt.Fprintf(c.conn, "<message to='%s' type='%s' xml:lang='en'>"+
		"<body>%s</body>"+
		"<html xmlns='http://jabber.org/protocol/xhtml-im'><body xmlns='http://www.w3.org/1999/xhtml'>%s</body></html></message>",
		xmlEscape(chat.Remote), xmlEscape(chat.Type), xmlEscape(chat.Text), chat.Text)
}
// SendHtml sends the message as HTML as defined by XEP-0071