...
if ( $session->is_new() ) {
    # Make CGI::Session think no save is needed
    # by simulating a call to flush.
    $session->{_STATUS} = &CGI::Session::SYNCED;

    # Make sure we don't use the session by accident.
    undef $session;
} else {
...

##</code><code>##

...
if ( $session->is_new() ) {
    $session->flush();   # Force it to be saved before it's deleted.
    $session->delete();
} else {
...

##</code><code>##

...
if ( $session->is_new() ) {
    $session->delete();
    eval { undef $session; };
} else {
...