websocket_client使う。
ネタ元
- https://blogs.msdn.microsoft.com/vcblog/2014/06/25/c-rest-sdk-websocket-client/
- https://github.com/Microsoft/cpprestsdk/wiki/Web-Socket
- http://emma.memect.com/t/77d50c99b34f5410f6a6a013b02a3495839c874673864f19c5de783b2be43d0b/Using%20C++%20to%20Connect%20to%20Web%20Services%20%20-%20Steve%20Gates%20-%20CppCon%202014.pdf
