code: func GetSchedulableMulticastQueueItems(db sqlx.Ext, count int) ([]MulticastQueueItem, error) {
  	var items []MulticastQueueItem
  	err := sqlx.Select(db, &items, `
  		select
  			*
  		from
  			multicast_queue
  		where
  			schedule_at <= $2
  		order by
  			id
  		limit $1
  		for update skip locked
  	`, count, time.Now())
  	if err != nil {
  		return nil, handlePSQLError(err, "select error")
  	}
  
  	return items, nil
  }
docs: // GetSchedulableMulticastQueueItems returns a slice of multicast-queue items
  // for scheduling.
  // The returned queue-items will be locked for update so that this query can
  // be executed in parallel.