PartsDifference returns a - b.

PartsIntersect returns the intersection of a and b.

SortParts sorts parts by (Path, Offset).

ToCanonicalPath returns canonical path by replacing local directory separators with `/`.

MaxPartSize is the maximum size for each part.

DeleteAllObjectVersions is a flag for whether to prune previous object versions when deleting an object.

Part is an atomic unit for transfer during backup / restore.

OriginFS is an interface for remote origin filesystem.

RemoteFS is a filesystem where backups are stored.