presto-main/src/main/java/io/prestosql/operator/scalar/VarbinaryFunctions.java/VarbinaryFunctions/toHex
class VarbinaryFunctions:    @Description("encode binary data as hex")
    @ScalarFunction
    @SqlType(StandardTypes.VARCHAR)
    public static Slice toHex(@SqlType(StandardTypes.VARBINARY) Slice slice)
    {
        return Slices.utf8Slice(BaseEncoding.base16().encode(slice.getBytes()));
    }