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.
{
            auto col_to = ColumnFixedString::create(Impl::length);
            const typename ColumnFixedString::Chars & data = col_from_fix->getChars();
            const auto size = col_from_fix->size();
            auto & chars_to = col_to->getChars();
            const auto length = col_from_fix->getN();
            chars_to.resize(size * Impl::length);
            for (size_t i = 0; i < size; ++i)
            {
                Impl::apply(
                    reinterpret_cast<const char *>(&data[i * length]), length, reinterpret_cast<uint8_t *>(&chars_to[i * Impl::length]));
            }
            return col_to;
        }
        else
            throw Exception("Illegal column " + arguments[0].column->getName()
                    + " of first argument of function " + getName(),
                ErrorCodes::ILLEGAL_COLUMN);
    }
};
DECLARE_MULTITARGET_CODE(
template <typename Impl, typename Name>
class FunctionIntHash : public IFunction
{
public:
    static constexpr auto name = Name::name;
private:
    using ToType = typename Impl::ReturnType;
    template <typename FromType>
    ColumnPtr executeType(const ColumnsWithTypeAndName & arguments) const