Traefik Proxy Protocol Support ?!?

Hi,

does traefik supports proxy protocol for tcp services - I mean not on the listening side, which it seems to support, but on the side where the request / connection is made to the server?!?

The documentation isn't very clear to me at this point...

Reason: I want to run a smtp server in a docker swarm behind traefik with tcp routing, and I need to know the real client IP in my smtp container.