Is there any way to include MySQL expressions like NOW() in the current build of ZF2 (2.0.0beta4) through Zend\Db and/or TableGateway insert()/update() statements?

Here is a related post on the mailing list, though it hasn't been answered: http://zend-framework-community.634137.n4.nabble.com/Zend-Db-Expr-and-Transactions-in-ZF2-Db-td4472944.html

It appears that ZF1 used something like:

    $data = array( 
        'update_time'   => new \Zend\Db\Expr("NOW()") 
    ); 

And after looking through Zend\Db\Sql\Expression I tried:

    $data = array(
        'update_time' => new \Zend\Db\Sql\Expression("NOW()"),
    );

But get the following error:

Catchable fatal error: Object of class Zend\Db\Sql\Expression could not be converted to string in /var/www/vendor/ZF2/library/Zend/Db/Adapter/Driver/Pdo/Statement.php on line 256

As recommended here: http://zend-framework-community.634137.n4.nabble.com/ZF2-beta3-Zend-Db-Sql-Insert-new-Expression-now-td4536197.html I'm currently just setting the date with PHP code, but I'd rather use the MySQL server as the single source of truth for date/times.

    $data = array(
        'update_time' => date('Y-m-d H:i:s'),
    );

Thanks, I appreciate any input!