func (c *Client) Close() {
	atomic.StoreInt32(&c.connected, closed)
}

// NewClient - returns new REST client.
func NewClient(uu *url.URL, tr http.RoundTripper, newAuthToken func(aud string) string) *Client {
	connected := int32(online)
	urlStr := uu.String()
	u, err := url.Parse(urlStr)
	if err != nil {
		// Mark offline, with no reconnection attempts.
		connected = int32(offline)