src/Services/BaseService.php
protected function buildMultipartFormDataFilePayload($name, $attachment)
    {
        return sprintf(
            '%s%s%s%s%s',
            '--boundary'.self::CRLF,
            'Content-Disposition: form-data; name="'.$name.'"; filename="picture"'.self::CRLF,
            'Content-Type: '.$attachment['mimeType'].self::CRLF.self::CRLF,
            $attachment['data'].self::CRLF,
            '--boundary--'
        );
    }
protected function buildMultipartFormDataFilePayload($name, $attachment)
    {
        return sprintf(
            '%s%s%s%s%s',
            '--boundary'.self::CRLF,
            'Content-Disposition: form-data; name="'.$name.'"; filename="picture"'.self::CRLF,
            'Content-Type: '.$attachment['mimeType'].self::CRLF.self::CRLF,
            $attachment['data'].self::CRLF,
            '--boundary--'
        );
    }
Builds the file part of a multipart/form-data request body.

@param string $name
@param array $attachment

@return string The file part of a multipart/form-data request body.