code: func (l *lagLogger) Store(readOffset, highWaterMark int64, ts time.Time) {
  	lag := highWaterMark - readOffset
  	if lag < 0 {
  		return
  	}
  
  	measurement := offsetMeasurement{
  		readOffset:    readOffset,
  		highWaterMark: highWaterMark,
  		ts:            ts,
  	}
  	if len(l.measurements) < cap(l.measurements) {
  		l.measurements = append(l.measurements, measurement)
  		l.pos = len(l.measurements) - 1
  		return
  	}
  
  	l.pos++
  
  	if l.pos >= cap(l.measurements) {
  		l.pos = 0
  	}
  	l.measurements[l.pos] = measurement
  }
docs: // Store saves the current offsets and timestamp, potentially overwriting an old value
  // if needed.
  // Note: negative values of highWaterMark - readOffset are ignored.  We rely on previous data - if any - in such case.
  // negative values can happen upon a rollover of the offset counter