Function run_async 

pub async fn run_async(
    token: CancellationToken,
    listener: Option<Arc<dyn SyncStatusListener>>,
    storage_dir: &str,
    db_file_path: &str,
    api_endpoint: &str,
    remote_token: &str,
    namespace_id: i32,
    download_only: bool,
) -> Result<(), SyncError>

Runs local files watch and sync from/to remote continuously.