Description:
------------
When extending \SessionHandler's read method and calling the parent method the session data is still read from the session returned by the PHP function "session_id()" instead of the defined session id.

As a workaround it is possible to use `session_id('mycustomsession')` before reading the value and resetting it to the previous value. Note that the test script is not a real-world scenario and just illustrating the behaviour.

Test script:
---------------
<?php

class CustomReadHandler extends \SessionHandler {

	public function read($session_id) {
		parent::read('mycustomsession');
	}
}
session_set_save_handler(new CustomReadHandler(), true);

session_start();
$_SESSION['foo'] = 'bar';
var_dump($_SESSION);

Expected result:
----------------
The session mycustomsession is used. Instead the session returned by "session_id" id is used. Data is thus stored in sess_jtmv4c76rqarqpt475ptkskr15 instead of sess_mycustomsession.

Actual result:
--------------
Data is read from the session defined by the PHP function "session_id()".