libc++abi: terminating with uncaught exception of type std::__1::future_error: The associated promise has been destructed prior to the associated state becoming ready.

[jzhoucdc]

刚开始用这个框架，跑首页简单加法的测试代码，租用的远程机器跑的服务端，自己本机跑客户端报错。

libc++abi: terminating with uncaught exception of type std::__1::future_error: The associated promise has been destructed prior to the associated state becoming ready.