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
	dst   chan [][]string // result of block decode

)

// Reader - JSON record reader for S3Select.
type Reader struct {
	args    *json.ReaderArgs
	input   chan simdjson.Stream
	decoded chan simdjson.Object

	// err will only be returned after decoded has been closed.
	err          *error
	readCloser   io.ReadCloser
	onReaderExit func()

	exitReader chan struct{}
	readerWg   sync.WaitGroup
}

// Read - reads single record.