arith_service.proto

// protoc --gogofaster_out=. arith_service.proto
// mv arith_service.pb.go arith_service_test.go 
syntax = "proto3";

package client;

message ProtoArgs { 
    int32 A = 1;
    int32 B = 2;
}

message ProtoReply { 
    int32 C = 1;
}