Magestead\Service\UsageApi::getFieldsString PHP Method

    protected function getFieldsString()
    {
        $fields_string = '';
        foreach ($this->_params as $key => $value) {
            $fields_string .= $key . '=' . $value . '&';
        }
        rtrim($fields_string, '&');
        return $fields_string;
    }