support pkg/object/cifs.go

[zhengp570]

What would you like to be added:
support pkg/object/cifs.go
Why is this needed:
I see that version 1.2.1 provides pkg/object/nfs.go, which significantly improves performance for migrating NFS files. However, I haven't seen support for CIFS. I've written a simple demo, and it can improve performance by 60% compared to the mount mode. Could you provide corresponding support for CIFS?

[davies]

Can you send a PR for that?