sbintime_t
sbintime_t timestamp, time;
sbintime_t keep_alive_timestamp;
sbintime_t keep_alive_timeout;
sbintime_t missing_tx_timeout;
#define SBT_1S ((sbintime_t)1 << 32)
static __inline sbintime_t
return (((sbintime_t)_bt.sec << 32) + (_bt.frac >> 32));
static __inline sbintime_t