function dedicatedEcho($message, $callback = '', $multicall = false)
    {
        if (!is_string($message)) {
            throw new InvalidArgumentException('message = ' . print_r($message, true));
        }
        if (!is_string($callback)) {
            throw new InvalidArgumentException('callback = ' . print_r($callback, true));
        }

        return $this->execute('Echo', array($message, $callback), $multicall);
    }