code: func EventIDForDeviceBeforeTime(dev int32, before time.Time) uint64 {
  	tm := C.CFAbsoluteTime(before.Unix())
  	return uint64(C.FSEventsGetLastEventIdForDeviceBeforeTime(C.dev_t(dev), tm))
  }
docs: // EventIDForDeviceBeforeTime returns an event ID before a given time.