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: webrick.rb
    path of file: ./repos/stackneveroverflow/vendor/bundle/ruby/2.3.0/gems/rack-2.0.3/lib/rack/handler
    
    the code of the file until where you have to start completion: require 'webrick'
require 'stringio'
require 'rack/content_length'

# This monkey patch allows for applications to perform their own chunking
# through WEBrick::HTTP
    
      def self.run(app, options={})
        environment  = ENV['RACK_ENV'] || 'development'
        default_host = environment == 'development' ? 'localhost' : nil

        options[:BindAddress] = options.delete(:Host) || default_host
        options[:Port] ||= 8080
        @server = ::WEBrick::HTTPServer.new(options)
        @server.mount "/", Rack::Handler::WEBrick, app
        yield @server  if block_given?
        @server.start
      end