when a session is closed, use the packet manager to create a pseudo packet,
set the session to be closed as packet Exdata, and schedule it to the packet forwarding stage.
when the pseudo packet free, the session will be free.
when a session is closed, use the packet manager to create a pseudo packet,
set the session to be closed as packet Exdata, and schedule it to the packet forwarding stage.
when the pseudo packet free, the session will be free.