code: func (h *Histogram) RecordValues(v, n int64) error {
  	idx := h.countsIndexFor(v)
  	if idx < 0 || int(h.countsLen) <= idx {
  		return fmt.Errorf("value %d is too large to be recorded", v)
  	}
  	h.counts[idx] += n
  	h.totalCount += n
  
  	return nil
  }
docs: // RecordValues records n occurrences of the given value, returning an error if
  // the value is out of range.