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

	return &Reader{
		args:       args,
		decoded:    ch,
		err:        err,
		readCloser: nil,
	}
}

// safeCloser will wrap a Reader as a ReadCloser.
// It is safe to call Close while the reader is being used.
type safeCloser struct {
	closed uint32
	r      io.Reader
}

func (s *safeCloser) Read(p []byte) (n int, err error) {
	if atomic.LoadUint32(&s.closed) == 1 {
		return 0, io.EOF
	}

// returns ETag of the content. Otherwise, it returns
// nil as ETag.
//
// Wrap provides an adapter for io.Reader implementations
// that don't implement the Tagger interface.
// It is mainly used to provide a high-level io.Reader
// access to the ETag computed by a low-level io.Reader:
//
//	content := etag.NewReader(r.Body, nil)
//
//	compressedContent := Compress(content)

// The sparse map is stored in the tar header if it's small enough.
// If it's larger than four entries, then one or more extension headers are used
// to store the rest of the sparse map.
//
// The Header.Size does not reflect the size of any extended headers used.
// Thus, this function will read from the raw io.Reader to fetch extra headers.
// This method mutates blk in the process.

		f.Modified = modified.UTC()

		// If legacy MS-DOS timestamps are set, we can use the delta between
		// the legacy and extended versions to estimate timezone offset.
		//
		// A non-UTC timezone is always used (even if offset is zero).
		// Thus, FileHeader.Modified.Location() == time.UTC is useful for
		// determining whether extended timestamps are present.
		// This is necessary for users that need to do additional time

	sha256 hash.Hash
}

// Options are optional arguments to NewReaderWithOpts, Options
// simply converts positional arguments to NewReader() into a
// more flexible way to provide optional inputs. This is currently
// used by the FanOut API call mostly to disable expensive md5sum
// calculation repeatedly under hash.Reader.
type Options struct {
	MD5Hex     string
	SHA256Hex  string
	Size       int64
	ActualSize int64
	DisableMD5 bool