How to use meta-training with PET?

[LiweiPeng]

@timoschick The PET results are very impressive for fewshot learning. For our scenario, we have big collection of data in classes that are related to our target fewshot classes, so I'd like to take advantage of them using something like meta-training. My questions are:

1. How to use PET together with meta-training?
2. If not supported yet, what's PET plan to support this scenario?
   Thanks.