Publications and $addToSet queries

performance
1

Hey everyone!
I have a question about how publications handle $addToSet queries.
Lets say we had a publication that publishes changes on our user collection.
The cursor is giving us an array property on the documents among other things.
If we update a user document and use $addToSet, does the oplog driver know how to handle this case? or does it fall back to using the polling/diff method?
How does Meteor handle this? Would all subscriptions to this publication trigger a read on the users collection for diff purposes?

Meteor.publish('myUser', function () {
  const handle = this;
  const userCursor = Meteor.users.find({
    _id: this.userId,
  }, { 
    fields: {
      arrayProperty: 1, 
    }
  });
  const observeHandle = userCursor.observe({
    ...
    changed: function (doc) {
      handle.added('users', userId, user);
    },
    ...
  });
});

//Update a user doc with $addToSet
Meteor.users.update({ _id: '123' }, {
  $addToSet: {
    arrayProperty: 'test',
  },
});
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