https://github.com/ClickHouse/ClickHouse/blob/9a48cf0da8badfc5f3da08611eb44961aa28e3f6/src/Functions/FunctionsHashing.h#L669-L671

There's a call to `blake3_free_char_pointer` that passes ownership of the pointer back to Rust (which then frees the memory), then there's a call to `std::string`'s constructor that accepts that now-freed pointer.
template <typename Impl>
class FunctionAnyHash : public IFunction
{
public:
    static constexpr auto name = Impl::name;
private:
    using ToType = typename Impl::ReturnType;
    template <typename FromType, bool first>
    void executeIntType(const IColumn * column, typename ColumnVector<ToType>::Container & vec_to) const
    {
        using ColVecType = ColumnVectorOrDecimal<FromType>;
        if (const ColVecType * col_from = checkAndGetColumn<ColVecType>(column))
        {
            const typename ColVecType::Container & vec_from = col_from->getData();
            size_t size = vec_from.size();
            for (size_t i = 0; i < size; ++i)
            {
                ToType h;
                if constexpr (Impl::use_int_hash_for_pods)
                {
                    if constexpr (std::is_same_v<ToType, UInt64>)
                        h = IntHash64Impl::apply(bit_cast<UInt64>(vec_from[i]));
                    else
                        h = IntHash32Impl::apply(bit_cast<UInt32>(vec_from[i]));