code: public void read() {
      if (isTransient) {
        AVIMMessage lastMessage = getLastMessage();
        Map<String, Object> params = new HashMap<String, Object>();
        if (null != lastMessage) {
          params.put(Conversation.PARAM_MESSAGE_QUERY_MSGID, lastMessage.getMessageId());
          params.put(Conversation.PARAM_MESSAGE_QUERY_TIMESTAMP, lastMessage.getTimestamp());
        }
        InternalConfiguration.getOperationTube().markConversationRead(client.getClientId(), conversationId, getType(), params);
      }
    }
docs: 清除未读消息