Function pull_artifacts 

pub fn pull_artifacts<S: BackendSyncClient + ?Sized>(
    sync_client: &S,
    ito_path: &Path,
    change_id: &str,
    backup_dir: &Path,
) -> CoreResult<ArtifactBundle>

Pull artifacts from the backend for a change and write them locally.

Creates a timestamped backup snapshot under backup_dir before writing. Returns the pulled artifact bundle.