code: func (mb *MetricBatcher) BatchCounter(name string) BatchCounterChainer {
  	return batchCounterChainer{
  		batcher: mb,
  		name:    name,
  		tags:    make(map[string]string),
  	}
  }
docs: // BatchCounter returns a BatchCounterChainer which can be used to prepare
  // a counter event before batching it up.