code: @Override
  	public void receiveCommandMessage(Session client, String json) {
  		MessageFromClient message = MessageFromClient.createFromJson(json);
  		logger.debug("Receive call message in websocket '{}' for session '{}'", message.getId(), client.getId());
  		callServiceManager.sendMessageToClient(message, client);
  	}
docs: A message is a call service request or subscribe/unsubscribe topic
  
  @param client
  @param json