Description:
------------
Output buffering does capture the output of print() and echo() but apparently not anything that goes to STDOUT (php://stdout) via fwrite().

That should preferably be fixed or at least be documented.

Reproduce code:
---------------
$ cat t.php
<?php
error_reporting(E_ALL);

ob_start();

echo "does work\n";

$f = fopen('php://stdout', 'w');
fwrite($f, "does not work\n");
fclose($f);

$v = ob_get_contents();
ob_end_clean();

print("CAPTURED: $v\n");


Expected result:
----------------
$ php t.php

CAPTURED: does not work
does work

Actual result:
--------------
$ php t.php
does not work
CAPTURED: does work