code: protected void init() {
          // 从ThreadLocal取出当前长连接，request等信息设置进去，需要接到请求时提前设置到ThreadLocal里
          RpcInternalContext context = RpcInternalContext.getContext();
          asyncContext = (AsyncContext) context.getAttachment(RpcConstants.HIDDEN_KEY_ASYNC_CONTEXT);
          request = (SofaRequest) context.getAttachment(RpcConstants.HIDDEN_KEY_ASYNC_REQUEST);
      }
docs: 初始化数据