This decorator provides a memory cache layer. It does NOT persist through requests,
only in the current execution of the script. You can turn off prefetch
if you want small network load (but it will increase the number of queries to the database)
<?php
$tr = new Translation2($driver, $dbinfo, $params);
$tr =& $tr->getDecorator('CacheMemory');
$tr->setOption('prefetch', true); //default value is true
?>