void OnUpdateInstalled( object sender, HelpUpdateDownloadedEventArgs e )
{
var vm = FindOrCreateVm( e.Plugin );
vm.State = PluginUpdateState.Installed;
}
void OnUpdateDownloaded( object sender, HelpUpdateDownloadedEventArgs e )
{
var vm = FindOrCreateVm( e.Plugin );
vm.State = PluginUpdateState.WaitingForInstall;
vm.DownloadResult = e.DownloadResult;
}