如何从Zend框架工作2会话中检索值?

i just got a dump on Session in ZF2

Zend\Session\Storage\SessionStorage Object
(
[isImmutable:protected] => 
[storage:ArrayObject:private] => Array
    (
        [__ZF] => Array
            (
                [_REQUEST_ACCESS_TIME] => 1359526796.5079
                [FlashMessenger] => Array
                    (
                        [EXPIRE_HOPS] => Array
                            (
                                [hops] => 1
                                [ts] => 1359526775.9345
                            )

                    )

            )

        [FlashMessenger] => ArrayObject Object
            (
                [storage:ArrayObject:private] => Array
                    (
                        [default] => Zend\Stdlib\SplQueue Object
                            (
                                [flags:SplDoublyLinkedList:private] => 4
                                [dllist:SplDoublyLinkedList:private] => Array
                                    (
                                        [0] => Authentication successful.
                                    )

                            )

                    )

            )

        [zf_tutorial] => ArrayObject Object
            (
                [storage:ArrayObject:private] => Array
                    (
                        [storage] => hello
                    )

            )

        [zftutorial] => ArrayObject Object
            (
                [storage:ArrayObject:private] => Array
                    (
                        [role] => user
                    )

            )



    )
)

i just dont know how to get retrieve

[role] => user

Extracted from here

Some examples of zf2 sessions usage:

Session creation:

use Zend\Session\Container;

$session = new Container('zftutorial');

Check that key exists in session:

$session->offsetExists('role')

Getting value from the session by key:

$role= $session->offsetGet('role');

Setting value in session:

$session->offsetSet('role', $role);