presto-main/src/main/java/io/prestosql/type/QuantileDigestOperators.java/QuantileDigestOperators/castFromVarbinaryDouble
class QuantileDigestOperators:    @ScalarOperator(CAST)
    @SqlType("qdigest(double)")
    public static Slice castFromVarbinaryDouble(@SqlType(StandardTypes.VARBINARY) Slice slice)
    {
        return slice;
    }