defer r.readerWg.Done()
		for {
			q := queueItem{
				input: next,
				dst:   make(chan [][]string, 1),
				err:   nextErr,
			}
			select {
			case <-r.close:
				return
			case r.queue <- &q:
			}

			select {
			case <-r.close:
				return
			case r.input <- &q:
			}
			if nextErr != nil {
				// Exit on any error.
				return
			}