start server
go run main.go
server app outputs length of binary request
curl http://localhost:8080/calc -d '{"op":"*","args":[1,2,3,6]}'
# or
curl http://localhost:8080/calc -d @sample.json
go run test/protobuf_requestor.go
# or
curl http://localhost:8080/calcpb --data-binary @dat
go get -u github.com/golang/protobuf/protoc-gen-go
sudo apt install protobuf-compiler
protoc -I=api --go_out=api api/*.proto
gotest ./... -v