Change used id for sending just to one client (#468)
Change used id for sending just to one client (#468)

**What actually happens**
It just does not send the messages while using the id showed in the sample.

**How to reproduce**
Just run an app which uses the sample code from your docs and try to send the message to just one client - the one which has been connected to topic.

**The remediation**
Just use `$connection->WAMP->sessionId` instead.
GeniusesOfSymfony/WebSocketBundle,GeniusesOfSymfony/WebSocketBundle