code: func NewNonCumulativeDistribution(name string, description string, metadata *types.MetricMetadata, bucketer *distribution.Bucketer, fields ...field.Field) NonCumulativeDistribution {
  	if metadata == nil {
  		metadata = &types.MetricMetadata{}
  	}
  	m := &nonCumulativeDistributionMetric{
  		metric: metric{
  			MetricInfo: types.MetricInfo{
  				Name:        name,
  				Description: description,
  				Fields:      fields,
  				ValueType:   types.NonCumulativeDistributionType,
  			},
  			MetricMetadata: *metadata,
  		},
  		bucketer: bucketer,
  	}
  	registry.Add(m)
  	return m
  }
docs: // NewNonCumulativeDistribution returns a new non-cumulative-distribution-valued
  // metric.