silverstripe-framework: DataObject->write() without changes does not update LastEdited in the Database, but does on the instance

write() updates LastEdited on the object itself, but only writes it to database if the DataObject has changes.

$foo = Foo::get()->first();
echo $foo->LastEdited; // 2014-11-14 18:46:14
$foo->write();
echo $foo->LastEdited; // 2014-11-14 22:00:32
$foo = Foo::get()->first();
echo $foo->LastEdited; // 2014-11-14 18:46:14