C → S {line:…, type: 'bye'}
bye – close line. Usually sent by client before it closes a connection line.
C → S → C {line:…, type: 'bye'}
If client is in call with someone server forwards bye message to other end of call. It then works similar to esc message ending call.
C → S {type: 'bye'}
If websocket connection is about to be closed by client it sends a bye message without any line argument as final message.