class RestClient::Payload::UrlEncoded

def build_stream(params = nil)
  @stream = StringIO.new(flatten_params(params).map do |k, v|
    "#{k}=#{escape(v)}"
  end.join("&"))
  @stream.seek(0)
end

def headers
  super.merge({ 'Content-Type' => 'application/x-www-form-urlencoded' })
end