code: public static void clientAsyncReceivedPrepare() {
          if (openTrace) {
              try {
                  tracer.clientAsyncReceivedPrepare();
              } catch (Exception e) {
                  if (LOGGER.isWarnEnabled()) {
                      LOGGER.warn(e.getMessage(), e);
                  }
              }
          }
      }
docs: 4.3 客户端异步收到响应，做准备，例如设置到上下文