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: httpproxy.rb
    path of file: ./repos/ruby-packer/ruby/lib/webrick
    
    the code of the file until where you have to start completion: # frozen_string_literal: false
#
# httpproxy.rb -- HTTPProxy Class
#
# Author: IPR -- Internet Programming with Ruby -- writers
# Copyright (c) 2002 GOTO Kentaro
# Copyright (c) 2002 Internet Programming with Ruby writers. All rights
# reserved.
#
# $IPR: httpproxy.rb,v 1.18 2003/03/08 18:58:10 gotoyuzo Exp $
# $kNotwork: straw.rb,v 1.3 2002/02/12 15:13:07 gotoken Exp $

require_relative "httpserver"
require "net/http"

module WEBrick

  NullReader = Objec
    
    def split_field(f) f ? f.split(/,\s+/).collect{|i| i.downcase } : [] end

    def choose_header(src, dst)
      connections = split_field(src['connection'])
      src.each{|key, value|
        key = key.downcase
        if HopByHop.member?(key)          || # RFC2616: 13.5.1
           connections.member?(key)       || # RFC2616: 14.10
           ShouldNotTransfer.member?(key)    # pragmatics
          @logger.debug("choose_header: `#{key}: #{value}'")
          next
        end
        dst[key] = value
      }
    end