start (Merb::Rack::Irb)

    # File lib/merb-core/rack/adapter/irb.rb, line 149
          def self.start(opts={})
            m = Merb::Rack::Console.new
            m.extend Merb::Test::RequestHelper
            m.extend ::Webrat::Methods if defined?(::Webrat)
            Object.send(:define_method, :merb) { m }
            ARGV.clear # Avoid passing args to IRB
            m.open_sandbox! if sandboxed?
            require 'irb'
            require 'irb/completion'
            if File.exists? ".irbrc"
              ENV['IRBRC'] = ".irbrc"
            end
            IRB.start
            at_exit do merb.close_sandbox! if sandboxed? end
            exit
          end