Amp\Artax\FormBody::getFormEncodedBodyString PHP Method

    private function getFormEncodedBodyString()
    {
        $fields = [];
        foreach ($this->fields as $fieldArr) {
            list($name, $value) = $fieldArr;
            $fields[$name][] = $value;
        }
        foreach ($fields as $key => $value) {
            $fields[$key] = isset($value[1]) ? $value : $value[0];
        }
        return http_build_query($fields);
    }