Example:

`event.errorCode = -118`
`event.errorDescription = "CONNECTION_TIMED_OUT"`

or to be ISO with Google Chrome:
`event.errorDescription = "ERR_CONNECTION_TIMED_OUT"`

_See https://src.chromium.org/svn/trunk/src/net/base/net_error_list.h_

Would that make sense?

atom/renderer/atom_renderer_client.cc
#include "atom/renderer/atom_renderer_client.h"
#include <string>
#include <vector>
#include "atom/common/api/api_messages.h"
#include "atom/common/api/atom_bindings.h"
#include "atom/common/api/event_emitter_caller.h"
#include "atom/common/color_util.h"
#include "atom/common/node_bindings.h"
#include "atom/common/node_includes.h"
#include "atom/common/options_switches.h"
#include "atom/renderer/atom_render_view_observer.h"
#include "atom/renderer/guest_view_container.h"
#include "atom/renderer/node_array_buffer_bridge.h"
#include "base/command_line.h"
#include "chrome/renderer/media/chrome_key_systems.h"
#include "chrome/renderer/pepper/pepper_helper.h"
#include "chrome/renderer/printing/print_web_view_helper.h"
#include "chrome/renderer/tts_dispatcher.h"
#include "content/public/common/content_constants.h"
#include "content/public/renderer/render_frame.h"
#include "content/public/renderer/render_frame_observer.h"