bbr_log_exit_gain
bbr_log_exit_gain(bbr, cts, 4);
bbr_log_exit_gain(bbr, cts, 3);
bbr_log_exit_gain(bbr, cts, 2);
bbr_log_exit_gain(bbr, cts, 0);
bbr_log_exit_gain(bbr, cts, 1);