code: function maybeCopyIcons(options, appPath, callback) {
    if (!options.icon) {
      callback();
      return;
    }
  
    if (options.platform === 'darwin' || options.platform === 'mas') {
      callback();
      return;
    }
  
    // windows & linux
    // put the icon file into the app
    const destIconPath = path.join(appPath, 'resources/app');
    const destFileName = `icon${path.extname(options.icon)}`;
    copy(options.icon, path.join(destIconPath, destFileName), (error) => {
      callback(error);
    });
  }
docs: For windows and linux, we have to copy over the icon to the resources/app folder, which the
  BrowserWindow is hard coded to read the icon from
  @param {{}} options
  @param {string} appPath
  @param callback