How to enable sticky session with Websocket on Apache Version 2.4.6

Issue

We have a problem with the implementation of load balancing and sticky session in websockets requests. This is our configuration:

Header add Set-Cookie "ROUTEID=.%{BALANCER_WORKER_ROUTE}e; path=/" env=BALANCER_ROUTE_CHANGED
<Proxy balancer://websocket>
    BalancerMember ws://x.x.x.x:8081 route=master
    BalancerMember ws://x.x.x.x:8081 route=slave
    ProxySet stickysession=ROUTEID
</Proxy>