Subclass hook to actually persist the given <tt>Session</tt> instance to the underlying EIS.
@param session the Session instance to persist to the EIS.
@return the id of the session created in the EIS (i.e. this is almost always a primary key and should be the
value returned from {@link hunt.shiro.session.Session#getId() Session.getId()}.
Subclass hook to actually persist the given <tt>Session</tt> instance to the underlying EIS.
@param session the Session instance to persist to the EIS. @return the id of the session created in the EIS (i.e. this is almost always a primary key and should be the value returned from {@link hunt.shiro.session.Session#getId() Session.getId()}.