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: builder.rb
    path of file: ./repos/rack-app/lib/rack/app/endpoint
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

require 'rack/builder'
class Rack::App::Endpoint::Builder
  def initialize(config)
    @config = config
  end

  def to_app
    build.to_app

    
  def apply_catcher_on_need(builder)
    at_least_one_hook_requested = @config.ancestor_apps.any? do |app_class|
      app_class.before.length + app_class.after.length > 0
    end

    if at_least_one_hook_requested
      builder.use(Rack::App::Endpoint::Catcher, @config)
    end