code: func (h *Histogram) Distribution() (result []Bar) {
  	i := h.iterator()
  	for i.next() {
  		result = append(result, Bar{
  			Count: i.countAtIdx,
  			From:  h.lowestEquivalentValue(i.valueFromIdx),
  			To:    i.highestEquivalentValue,
  		})
  	}
  
  	return result
  }
docs: // Distribution returns an ordered list of bars of the
  // distribution of recorded values, counts can be normalized to a probability