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.
else if (which.isDate32())
            return executeType<Int32>(arguments);
        else if (which.isDateTime())
            return executeType<UInt32>(arguments);
        else if (which.isDecimal32())
            return executeType<Decimal32>(arguments);
        else if (which.isDecimal64())
            return executeType<Decimal64>(arguments);
        else
            throw Exception("Illegal type " + arguments[0].type->getName() + " of argument of function " + getName(),
                ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
    }
};
) 
template <typename Impl, typename Name>
class FunctionIntHash : public TargetSpecific::Default::FunctionIntHash<Impl, Name>
{
public:
    explicit FunctionIntHash(ContextPtr context) : selector(context)
    {
        selector.registerImplementation<TargetArch::Default,
            TargetSpecific::Default::FunctionIntHash<Impl, Name>>();
    #if USE_MULTITARGET_CODE
        selector.registerImplementation<TargetArch::AVX2,
            TargetSpecific::AVX2::FunctionIntHash<Impl, Name>>();
        selector.registerImplementation<TargetArch::AVX512F,
            TargetSpecific::AVX512F::FunctionIntHash<Impl, Name>>();
    #endif
    }
    ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr & result_type, size_t input_rows_count) const override