@Override
  final double doGetRate() {
    return SECONDS.toMicros(1L) / stableIntervalMicros;
  }
The time when the next request (no matter its size) will be granted. After granting a request,
this is pushed further in the future. Large requests push this further than small requests.
src/main/java/com/google/maps/internal/ratelimiter/SmoothRateLimiter.java