Does Nginx support PROXY Protocol making requests TO Varnish?

I've got nginx set up as the ssl endpoint / reverse proxy that then points to varnish which points to apache. That all works fine.

But I know varnish supports PROXY Protocol, and I know nginx does, too... on the server side. My question is does nginx support using PROXY Protocol on client requests TO varnish, in this case?

I've tried pointing it at the PROXY port but I get nothing out of it, so it doesn't seem like I've been able to get nginx to "speak" PROXY to varnish.

Is it possible?