code: func (mb *MetricBatcher) Close() {
  	mb.lock.Lock()
  	defer mb.lock.Unlock()
  
  	mb.closed = true
  	close(mb.closedChan)
  
  	mb.flush(mb.unsafeResetAndReturnMetrics())
  }
docs: // Closes the metrics batcher. Using the batcher after closing, will cause a panic.