*sender = None;

                                std::mem::drop(sender.take());

        self.download_changes_(c, Some(sender), changes_dir, full)
            .await
    }
    async fn download_changes_(
        &mut self,
        c: &[libpijul::pristine::Hash],
        mut sender: Option<&mut tokio::sync::mpsc::Sender<libpijul::pristine::Hash>>,
        changes_dir: &mut PathBuf,
        full: bool,
    ) -> Result<(), anyhow::Error> {

            if sender.send(_hash).await.is_err() {
                progress.abandon();
                break;

            if let Some(ref mut sender) = sender {
                if sender.send(_hash).await.is_err() {
                    progress.abandon();
                    break;
                }

        let (mut send, recv) = tokio::sync::mpsc::channel(100);
        self.download_changes(&hashes, &mut send, &mut repo.changes_dir, true)

        self.download_changes_(&hashes, None, &mut repo.changes_dir, true)

        std::mem::drop(recv);