channel_still_open
int channel_still_open(struct ssh *);
if (session_closed && !channel_still_open(ssh))
} else if (channel_still_open(ssh)) {
if (session_closed && !channel_still_open(ssh) &&
if (channel_still_open(ssh) || unused_connection_expiry == 0) {
now > unused_connection_expiry && !channel_still_open(ssh)) {