Can we use "ImportC" used yet?

[data pulverizer]

On Saturday, 23 October 2021 at 17:42:32 UTC, data pulverizer 
wrote:
> On Saturday, 23 October 2021 at 16:39:08 UTC, data pulverizer 
> wrote:
>> ```
>> ...
>> this(R_xlen_t n)
>>   {
>>     SEXPTYPE _real_ = SEXPTYPE.REALSXP;
>>     _data = protect(allocVector(_real_, n));
>>     unprotect(1);
>>   }
>> ...
>> ```
>
> Looking at that code, I realise didn't need the un/protect.

Actually it's more complicated than that. On construction I do 
need to call `protect` and call `unprotect` or `unprotect_ptr` 
when the function in which the object is created returns. At the 
moment, I'm not even sure (or more likely do not think) that it 
is suitable to call it as part of the destructor. Anyway, that's 
an aside.