Example: packing-lists

Every program reads packing-lists the same way
Every program writes packing-lists the same way
So we have one single interface to read packing-lists
$plist = OpenBSD::PackingList->read($fh);
$plist = OpenBSD::PackingList->fromfile("f");
And one interface to write them.
$plist->write($fh);
$plist->tofile("f");