// ReadFull returns ErrUnexpectedEOF.
			return dst[:n], err
		}
		dst = dst[:n]
		if err == io.ErrUnexpectedEOF {
			return dst, io.EOF
		}
	}
	// Read until next line.
	in, err := r.buf.ReadBytes('\n')
	dst = append(dst, in...)
	return dst, err
}

// csvSplitSize is the size of each block.
// Blocks will read this much and find the first following newline.

// calculation repeatedly under hash.Reader.
type Options struct {
	MD5Hex     string
	SHA256Hex  string
	Size       int64
	ActualSize int64
	DisableMD5 bool
	ForceMD5   []byte
}

// NewReaderWithOpts is like NewReader but takes `Options` as argument, allowing
// callers to indicate if they want to disable md5sum checksum.
func NewReaderWithOpts(ctx context.Context, src io.Reader, opts Options) (*Reader, error) {