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: handler.rb
    path of file: ./repos/lamby/lib/lamby
    
    the code of the file until where you have to start completion: module Lamby
  class Handler

    class << self

      def call(app, event, context, options = {})
        Lamby::ColdStartMetrics.instrument! if Lamby.config.cold_start_metrics?
    
    
    def call_app
      if Debug.on?(@event)
        Debug.call @event, @context, rack.env
      elsif rack?
        @status, @headers, @body = @app.call rack.env 
        set_cookies
        rack_response
      elsif lambdakiq?
        Lambdakiq.cmd event: @event, context: @context
      elsif lambda_cable?
        LambdaCable.cmd event: @event, context: @context
      elsif LambdaConsole.handle?(@event)
        LambdaConsole.handle(@event)
      elsif event_bridge?
        Lamby.config.event_bridge_handler.call @event, @context
      else
        [404, {}, StringIO.new('')]
      end