Goutte\Client::addPostFields PHP Method

    public function addPostFields(array $formParams, array &$multipart, $arrayName = '')
    {
        foreach ($formParams as $name => $value) {
            if (!empty($arrayName)) {
                $name = $arrayName . '[' . $name . ']';
            }
            if (is_array($value)) {
                $this->addPostFields($value, $multipart, $name);
            } else {
                $multipart[] = ['name' => $name, 'contents' => $value];
            }
        }
    }