if (_sampleRate === null) {
      console.warn('Call `FillRateHelper.setSampleRate` before `addListener`.');
    }
A helper class for detecting when the maximem fill rate of `VirtualizedList` is exceeded.
By default the sampling rate is set to zero and this will do nothing. If you want to collect
samples (e.g. to log them), make sure to call `FillRateHelper.setSampleRate(0.0-1.0)`.

Listeners and sample rate are global for all `VirtualizedList`s - typical usage will combine with
`SceneTracker.getActiveScene` to determine the context of the events.