read_all $fh, $buf, 5 or goto PARSE_ERROR;
my ($group_id, $expanded) = unpack('L< C', $buf);
my $uuid = _decode_uuid($group_id) // next;
read_all $fh, $buf, 5 or goto PARSE_ERROR;
my ($group_id, $expanded) = unpack('L< C', $buf);
my $uuid = _decode_uuid($group_id) // next;