Description:
------------
When zlib.output_compression is set to On, PHP always starts a new session.  I've looked at the headers, and PHP is always sending the cookie for the session id. The same happens using trans sid on, or manually appending the session id to the link. If zlib.output_compression is turned Off it's working ok.

Also, if I use ob_start("ob_gzhandler"); first and then ob_end_flush(); at the end, everything works as expected.

Reproduce code:
---------------
<?php
session_start();
if (!isset($_SESSION['count'])) {
   $_SESSION['count'] = 0;
} else {
   $_SESSION['count']++;
}
echo $_SESSION['count'];
echo " <a href=\"test.php">Refresh</a>";
?>

Expected result:
----------------
0, 1, 2, 3 , 4...

Actual result:
--------------
0, 0, 0, 0, 0...