Perl / LibXML：序列化时保持关闭标签

<tag />

<tag></tag>

$xml = $dom->serialize(0);
$xml =~ s/<([a-z]+)([^>]*?)\\/>/<$1$2><\\/$1>/gsi;

my $xml = do {
    local $XML::LibXML::setTagCompression = 1;
    $doc->toString();
};

use XML::LibXML;

my $x = XML::LibXML->new();
my $d = $x->load_xml(string => \"<xml><foo/></xml>\");

print $d->toString;

print qq{<?xml version=\"1.0\"?>\\n} . $d->toStringHTML();\'

<?xml version=\"1.0\"?>
<xml><foo/></xml>

<?xml version=\"1.0\"?>
<xml><foo></foo></xml>