pelican object sync to use temporary object names until transfers are complete

[stuartthebruce]

Pelican Service:

• Client
• Plugin
• Registry
• Director
• Origin
• Cache
• Other (please give the detail)

Is your feature request related to a problem? Please describe.

It would be helpful if pelican object sync had an option (perhaps the default?) to create temporary object names until/if transfers are complete to avoid applications accessing partial in-flight objects from the destination.

Describe the solution you'd like

Following the default behavior and options of rsync would be my first choice, i.e., temporary file by default and --inplace to opt-out.

[github-actions]

This issue is stale because it has been open for 60 days with no activity.

[turetske]

This is actually two different issues depending on uploads and downloads. I'm currently addressing the issue in the client for downloads. For uploads, we are addressing it with a plugin which will store objects in a temporary until the transfer is complete and then move/rename them properly and that will be the default. PelicanPlatform/xrootd-s3-http#109