Exhibits this bug:
1. start demo_whiteboard.pl
2.sewrver.
3. browse localhost:3080
4. click 3 times
5.open a second browser window on localhost:3080

 0659F1B0,000000000659F2A0)) --> websocket{code:1000,data:"",opcode:close}
Warning: [Thread chatroom_wait_2] Thread running "wait_for_sockets(chatroom{name:chat,queues:_G9{broadcast:<message_queue>(0000000005029DC0),event:<message_queue>(0000000005029D00),ready:<message_queue>(0000000005029C40),wait:<message_queue>(0000000005029B80)}})" died on exception: wait_for_input/3: stream `<stream>(000000000659F1B0,000000000659F2A0)' does not exist