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: post_stream_serializer_mixin.rb
    path of file: ./repos/discourse/app/serializers
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

module PostStreamSerializerMixin
  def se
    
  def post_stream
    result = { posts: posts }

    if include_stream?
      if !object.is_mega_topic?
        result[:stream] = object.filtered_post_ids
      else
        result[:isMegaTopic] = true
        result[:lastId] = object.last_post_id
      end