private async Task PushNotifyInboxMessageAsync(InboxEntity inbox)
{
Requires.NotNull(inbox, "inbox");
await Task.WhenAll(
this.PushNotifyInboxMessageWinStoreAsync(inbox),
this.PushNotifyInboxMessageWinPhoneAsync(inbox),
this.PushNotifyInboxMessageGoogleAsync(inbox),
this.PushNotifyInboxMessageAppleAsync(inbox));
}