Upon save/update failure - no way to get Id

[charlessolar]

When saving using the multi puts if something goes wrong there doesn't seem to be a way to get the RiakObjectId from the failed RiakResult.

For instance:

var options = new RiakPutOptions
{
    IfNoneMatch = true,
    IfNotModified = false,
    ReturnHead = true,
    ReturnBody = false
};
options.SetW(Quorum.WellKnown.Quorum);
var saved = await _client.Async.Put(_saves, options);

    foreach(var failure in saved.Where(x => !x.IsSuccess))
    {
        // ? failure.Id
        // ? failure.Key
     }

I even tried to hack it together by doing this:

for(var i = 0; i < saved.Count(); i++){
   if(!saved.ElementAt(i).IsSuccess)
       _saved.ElementAt(i).Key // the one that failed!
}

But it seems the result is not kept in order because i'm getting incorrect reports of keys :(