Support rest

[gangxie112]

Is your feature request related to a problem?

Rest is still play an import part in real projects. If the grpc framework could support it, it will be great. It seems that grpc donet still have some experimental project for it : grpc/grpc-dotnet#167

Describe the solution you'd like

Describe alternatives you've considered

Additional context

[ejona86]

This is a very large request and would need substantial investment to support, at least in C and Java (Go might be a bit easier, but it would still be involved). I'm happy it has been added in .Net, but that doesn't change much. For this we'd need a team to step up and be prepared to do the work and maintenance. And there's a lot of work involved to make the core support plain HTTP.

[Huddie]

@ejona86 what's the best workaround atm in java to support this?

[ST-DDT]

This one worked at some point, but it might need a little touch up.
https://github.com/yidongnan/grpc-spring-boot-starter/pull/207
I wouldnt call it ready for production yet.
I plan to improve it in the future if I have time for it. Please keep in mind that it uses a secondary webserver to serve the http requests/endpoint.