Description:
------------
Lambda functions and closures are AWESOME!

But they are not still supported as ob_start() argument.



Reproduce code:
---------------
function redirect($file)
{
    $handle = fopen($file, 'w');
    ob_start(function($buffer) use ($handle) {
        fwrite($handle, $buffer);
    });
}

redirect('output.html');
echo 'Hello World!'; 

Expected result:
----------------
Should work

Actual result:
--------------
Fatal error: ob_start(): No method name given: use ob_start(array($object,'method')) to specify instance $object and the name of a method of class Closure to use as output buffer.