I always use `Unevaluated[Sequence[]]` inside If as my "vanishing function". So techinically I just use Sequence[]. That seems straightforward
. But this is nothing new I see, it can be found by following some more links in the linked article above.
Things can be further sped up by giving If (or other functions, in particular Function) attribute SequenceHold temporarily, but I guess that is a hack.
