- Electron version: 1.1.0
- Operating system: Windows
- Use case: cleanup and reporting tasks executed on quit (headless), which may take time and should not prevent from opening a new instance.
- Proposed solutions:
  - new _app.releaseSingleInstance()_ API which free the singleInstance lock
  - replace _app.releaseSingleInstance()_ API by an event listener (which may be listened/unlistened)
  - [app.makeSingleInstance](https://github.com/electron/electron/blob/master/docs/api/app.md#appmakesingleinstancecallback) returns the result of the callback function. So we can choose to quit or not in a more accurate way.
  - Provide a communication channel between the new instance and the main one (in callback arguments)

atom/browser/api/atom_api_app.cc
base::Bind(&Browser::IsDefaultProtocolClient, browser))
      .SetMethod("setAsDefaultProtocolClient",
                 base::Bind(&Browser::SetAsDefaultProtocolClient, browser))
      .SetMethod("removeAsDefaultProtocolClient",
                 base::Bind(&Browser::RemoveAsDefaultProtocolClient, browser))
#if defined(OS_MACOSX)
      .SetMethod("hide", base::Bind(&Browser::Hide, browser))
      .SetMethod("show", base::Bind(&Browser::Show, browser))
      .SetMethod("setUserActivity",
                 base::Bind(&Browser::SetUserActivity, browser))
      .SetMethod("getCurrentActivityType",
                 base::Bind(&Browser::GetCurrentActivityType, browser))
#endif
#if defined(OS_WIN)
      .SetMethod("setUserTasks",
                 base::Bind(&Browser::SetUserTasks, browser))
#endif
      .SetMethod("setPath", &App::SetPath)
      .SetMethod("getPath", &App::GetPath)
      .SetMethod("setDesktopName", &App::SetDesktopName)
      .SetMethod("getLocale", &App::GetLocale)
#if defined(USE_NSS_CERTS)
      .SetMethod("importCertificate", &App::ImportCertificate)
#endif
      .SetMethod("makeSingleInstance", &App::MakeSingleInstance);
}
}  
}  
namespace {
void AppendSwitch(const std::string& switch_string, mate::Arguments* args) {