Upsert and push an item onto an array

mongoupsert.cs

var query = Query.And(
    Query.EQ("_id", post.Id),
    Query.NE("Comments._id", comment.Id));

var options = new MongoUpdateOptions { 
    Flags = UpdateFlags.Upsert, 
    SafeMode = SafeMode.False 
};

var update = Update.AddToSetWrapped("Comments", comment)
    .Inc("TotalComments", 1);

DataStore.GetCollection<CommentThread>()
    .Update(query, update, options);