Loadbalancing - gracefully disable containers

I am using the Swarm mode in 1.12. However I am missing quite important feature on the load balancer. I need to upgrade / downscale scale the service containers gracefully. That means I need the container to stop accepting new connections (= disable it on LB) and wait for all current connections to terminate. After that the container can be stopped.

Is there any way to do it or at least plan to implement it?