How to match up Amazon CloudSearch document update error with document

Amazon CloudSearch (at least v2) provides errors and warnings like:

{
    "status": "success",
    "warnings": [{
        "message": "Multi-valued field \"color\" has no value (near operation with index 949)"
    },
    {
        "message": "Multi-valued field \"color_id\" has no value (near operation with index 949)"
    }],
    "adds": 1000,
    "deletes": 0
}

where the only way to figure out which document had an issue is parsing the "near operation with index X" and plucking that index.

I've seen a post somewhere that seems to indicate it can return document_id as well, but I'm not sure where that comes from.

So my question has two parts:

1) How can CloudSearch return the document id in the error/warning message? 2) If #1 isn't possible, is the CloudSearch error/warning message index 0- or 1-based?