igbinary

When I do phpinfo() or php -i from the CLI, I get the following output: session Registered save handlers => files user sqlite memcached Registered serializer handlers => php php_binary wddx I was not aware that PHP serialization supported a binary format, and there does not appear to be anything in the documentation about it. I was going to use igbinary for session serialization to a memcached server, so I'm wondering how php_binary compares. The igbinary PHP extension does offer a new session serialize/deserialize handler that differs from PHP's own implementations, namely php and php_binary