As per the spec we could provide more meta data about the processed requests:

/**

• The requests that were sent to the server.
  *
• NOT REQUIRED: Drivers may choose to not provide this property.
  */
  processedRequests: Optional<Iterable<WriteModel>>;

/**

• The requests that were not sent to the server.
  *
• NOT REQUIRED: Drivers may choose to not provide this property.
  */
  unprocessedRequests: Optional<Iterable<WriteModel>>;