FS control messages ctl_function
[recover|send_sighup|hupall|pause [inbound|outbound]|resume [inbound|outbound]|shutdown [cancel|elegant|asap|now|restart]|sps|sps_peak_reset|sync_clock|sync_clock_when_idle|reclaim_mem|max_sessions|min_dtmf_duration [num]|max_dtmf_duration [num]|default_dtmf_duration [num]|min_idle_cpu|loglevel [level]|debug_level [level]]