docs: public float getNextFrequency(float delta) throws IOException
      {
          float last = frequencyCounter.getFrequency();
          float min = last-delta;
          float max = last+delta;
          while (true)
          {
              int sample = getSample();
              if (frequencyCounter.update(sample))
              {
                  float next = frequencyCounter.getFrequency();
                  if (next > max || next < min)
                  {
                      return next;
                  }
              }
          }
      }