grpc c++ / go async

[yon...@gmail.com]

Hello,

How grpc async is compared in c++ and go? how scalable grpc is in c++?
Can you add or explain how async call is mapped to os thread? currently I use go to connect to hounders / thousands machines via grpc is it possible in c++ if yes then will it better or worse?
Mixing the server / client with grpc different languages is recommended? for example grpc (c++) and clients will written in grpc (go) or server be in swift or rust (experimental projects).

Thank you,

Yoni