Description:
------------
PHP can't find a previously included class in user defined session write callback function. Class is used without any problem in open and read processes. 
The code works like a charme using PHP v. 5.2.9

Reproduce code:
---------------
http://137.204.215.224/bug/code.txt

Expected result:
----------------
Accessing Logger::log() method in each session's user defined callback functions to append dato to log file 
/tmp/debug.log content:
***************************   OPENING   ***************************
*************************** READING ***************************
*************************** WRITING ***************************
Done


Actual result:
--------------
/tmp/debug.log content:
***************************   OPENING   ***************************
*************************** READING ***************************


PHP Fatal error:  Class 'Logger' not found in /home/petrux/workspace/debug10/Session.php on line 41