Parameter value in upload APIs

Hello everyone,

I have a question about “resumeAt” parameter of “uploadToken.upload” method in case of a media file is uploaded without file chunk.
In https://developer.kaltura.com/workflows/Ingest_and_Upload_Media, sample codes set the “resummeAt” to -1.
On the other hand, in https://blog.kaltura.com/api-inside-out-kaltura-architecture/ and https://github.com/kaltura/webrtc-krecord/blob/master/upload_to_kaltura.php, the sample codes set the “resumeAt” to “null”.
In the PHP and the JavaScript, “null” equals to 0.

Which value should we use for “resumeAt”?
Or , the value of this parameter is not related to the result?

Thank you in advance for your assistance.

Best regards,