bufferPool   sync.Pool        // pool of []byte objects for input
	csvDstPool   sync.Pool        // pool of [][]string used for output
	close        chan struct{}    // used for shutting down the splitter before end of stream
	readerWg     sync.WaitGroup   // used to keep track of async reader.
}

// queueItem is an item in the queue.
type queueItem struct {
	input []byte          // raw input sent to the worker