We should also hook up a grpc-go client to test the interop with the tonic server.

Currently, in https://github.com/hyperium/tonic/blob/master/interop/test.sh we only test tonic client -> grpc-go server and tonic client to tonic server. We should add an additional client test that will go from a grpc-go client to tonic server.

At the moment this plugin generates two files for each processed *.proto file with names:

• <protofile>_transformer.go
• options.go

In this case it's hard to say were these files auto-generated or weren't by its names.

Use additional file extension for auto-generated files: *.pb.st.go, as a result files should be named as :

• <protofile>.pb.st.go
• options.pb.st.go