class HTTP::Message::Headers

def set_request_header
  return if @dumped
  @dumped = true
  keep_alive = Message.keep_alive_enabled?(@http_version)
  if !keep_alive and @request_method != 'CONNECT'
    set('Connection', 'close')
  end
  if @chunked
    set('Transfer-Encoding', 'chunked')
  elsif @body_size and (keep_alive or @body_size != 0)
    set('Content-Length', @body_size.to_s)
  end
  if @http_version >= '1.1' and get('Host').empty?
    if @request_uri.port == @request_uri.default_port
      # GFE/1.3 dislikes default port number (returns 404)
      set('Host', "#{@request_uri.hostname}")
    else
      set('Host', "#{@request_uri.hostname}:#{@request_uri.port}")
    end
  end
end