Function reenqueue_abandoned 

pub async fn reenqueue_abandoned<'a, E>(
    executor: E,
    queue: &str,
    worker: &str,
    task_ids: &Vec<String>,
) -> Result<u64, Error>
where
    E: Executor<'a, Database = Sqlite>,

Re-enqueue tasks that were being processed by dying a worker

This will be invoked during Backend::poll_close