You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: topic_tracking_state_serializer.rb
    path of file: ./repos/discourse/app/serializers
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

class TopicTrackingStateSerializer < ApplicationSerializer
  attributes :data, :meta

  def data
    serializer = TopicTrackingStateItemSerializer.new(nil, sc
    
  def data
    serializer = TopicTrackingStateItemSerializer.new(nil, scope: scope, root: false)
    # note we may have 1000 rows, avoiding serializer instansitation saves significant time
    # for 1000 rows this takes it down from 10ms to 3ms on a reasonably fast machine
    object.map do |item|
      serializer.object = item
      serializer.as_json
    end
  end

  def meta
    MessageBus.last_ids(
      TopicTrackingState::LATEST_MESSAGE_BUS_CHANNEL,
      TopicTrackingState::RECOVER_MESSAGE_BUS_CHANNEL,
      TopicTrackingState::DELETE_MESSAGE_BUS_CHANNEL,
      TopicTrackingState::DESTROY_MESSAGE_BUS_CHANNEL,
      TopicTrackingState::NEW_MESSAGE_BUS_CHANNEL,
      TopicTrackingState::UNREAD_MESSAGE_BUS_CHANNEL,
      TopicTrackingState.unread_channel_key(scope.user.id),
    )
  end
end