presto-spi/src/main/java/io/prestosql/spi/type/UnscaledDecimal128Arithmetic.java/UnscaledDecimal128Arithmetic/isZero
class UnscaledDecimal128Arithmetic:    public static boolean isZero(Slice decimal)
    {
        return getLong(decimal, 0) == 0 && getLong(decimal, 1) == 0;
    }