lt_millisecond
uint64_t now = lt_millisecond();
start = lt_millisecond();
remaining = duration - (int)(lt_millisecond() - start);
uint64_t now = lt_millisecond();
last_logged = lt_millisecond();
int tsleep = collect_end - lt_millisecond();
current_time = lt_millisecond();
current_time = lt_millisecond();
extern uint64_t lt_millisecond(void);