presto-main/src/main/java/io/prestosql/operator/aggregation/NumericHistogram.java/NumericHistogram/getBuckets
class NumericHistogram:    public Map<Double, Double> getBuckets()
    {
        compact();

        Map<Double, Double> result = new LinkedHashMap<>();
        for (int i = 0; i < nextIndex; i++) {
            result.put(values[i], weights[i]);
        }
        return result;
    }