protected function logCurlMessage($message, \DateTime $messageTimestamp)
    {
        if (!$this->debugLogFilePath) {
            throw new \RuntimeException('Debug log file path not defined.');
        }
        $logMessage = '[' . $messageTimestamp->format('Y-m-d H:i:s') . "] ----------------------------------------------------------\n" . $message . "\n\n";
        $logHandle = fopen($this->debugLogFilePath, 'a+');
        fwrite($logHandle, $logMessage);
        fclose($logHandle);
    }