This action applies one or more updates to the document.
Each request is validated before
being applied. If any request is not valid, then the entire request will
fail and nothing will be applied.
Some requests have replies to
give you some information about how they are applied. Other requests do
not need to return information; these each return an empty reply.
The order of replies matches that of the requests.
For example, suppose you call batchUpdate with four updates, and only the
third one returns information. The response would have two empty replies,
the reply to the third request, and another empty reply, in that order.
Because other users may be editing the document, the document
might not exactly reflect your changes: your changes may
be altered with respect to collaborator changes. If there are no
collaborators, the document should reflect your changes. In any case,
the updates in your request are guaranteed to be applied together