The PHP prototype is currently using mongoc_bulk_operation_execute() exclusively for write operations. This function returns an integer hint for the node servicing the write on success; however, no hint is returned if an error occurs. That's fine for client-side errors such as empty batches, but I think it'd be helpful to report the hint for server-side errors.

I understand we can't change the function signature, but can the hint be made accessible on the reply bson_t without breaking BC? Alternatively, is there another way that I can extract the hint immediately after an unsuccessful call to mongoc_bulk_operation_execute() (perhaps something similar to how mongoc_collection_get_last_error() works)?