throws IOException {
if (writeBitmaps == null)
throw new IOException(JGitText.get().bitmapsMustBePrepared);
long writeStart = System.currentTimeMillis();
final PackBitmapIndexWriterV1 iw = new PackBitmapIndexWriterV1(bitmapIndexStream);
iw.write(writeBitmaps, packcsum);
stats.timeWriting += System.currentTimeMillis() - writeStart;
}