Don't require the `--structure` argument.
ColumnPtr generate(const IColumn & column) override
    {
        return column.cloneResized(column.size());
    }
    void updateSeed() override
    {
    }
};
static void transformFixedString(const UInt8 * src, UInt8 * dst, size_t size, UInt64 seed)
{
    {
        SipHash hash;
        hash.update(seed);
        hash.update(reinterpret_cast<const char *>(src), size);
        seed = hash.get64();
    }
    UInt8 * pos = dst;
    UInt8 * end = dst + size;
    size_t i = 0;
    while (pos < end)
    {
        SipHash hash;
        hash.update(seed);
        hash.update(i);
        if (size >= 16)
        {
            char * hash_dst = reinterpret_cast<char *>(std::min(pos, end - 16));
            hash.get128(hash_dst);
        }
        else