code: public WriteResult<T, K> updateById(K id, DBUpdate.Builder update) throws MongoException {
          return this.update(createIdQuery(id), update.serialiseAndGet(objectMapper));
      }
docs: Performs an update operation.
  
  @param id     The id of the document to update
  @param update update with which to update <tt>query</tt>
  @return The write result
  @throws MongoException If an error occurred