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: package.rb
    path of file: ./repos/ruby-packer/ruby/lib/rubygems
    
    the code of the file until where you have to start completion: # -*- coding: utf-8 -*-
# frozen_string_literal: true
#--
# Copyright (C) 2004 Mauricio Julio Fern√°ndez Pradier
# See LICENSE
    
  def gzip_to(io) # :yields: gz_io
    gz_io = Zlib::GzipWriter.new io, Zlib::BEST_COMPRESSION
    gz_io.mtime = @build_time

    yield gz_io
  ensure
    gz_io.close
  end