return fmt.Errorf("error: short write")
		}
	}
	return nil
}

func (cfw *CoverageDataWriter) patchSegmentHeader(ws *slicewriter.WriteSeeker) error {
	// record position
	off, err := ws.Seek(0, io.SeekCurrent)
	if err != nil {
		return fmt.Errorf("error seeking in patchSegmentHeader: %v", err)
	}
	// seek back to start so that we can update the segment header
	if _, err := ws.Seek(0, io.SeekStart); err != nil {