WebSocketSession session = new TestWebSocketSession("s1");
webSocketHandler.afterConnectionEstablished(session);
TextMessage textMessage = StompTextMessageBuilder.create(StompCommand.SEND).headers("destination:/foo").build();
webSocketHandler.handleMessage(session, textMessage);
Message<?> message = channel.messages.get(0);
StompHeaderAccessor accessor = StompHeaderAccessor.getAccessor(message, StompHeaderAccessor.class);
assertNotNull(accessor);
assertFalse(accessor.isMutable());