presto-main/src/main/java/io/prestosql/cost/SymbolStatsEstimate.java/SymbolStatsEstimate/toString
class SymbolStatsEstimate:    @Override
    public String toString()
    {
        return toStringHelper(this)
                .add("range", format("[%s-%s]", lowValue, highValue))
                .add("nulls", nullsFraction)
                .add("ndv", distinctValuesCount)
                .add("rowSize", averageRowSize)
                .toString();
    }