Imports of package documentation

PathSynopsis
github.com/golang/protobuf/protoPackage proto provides functionality for handling protocol buffer messages.
github.com/golang/protobuf/protoc-gen-go/generatorPackage generator is deprecated.
github.com/golang/protobuf/protoc-gen-go/grpcPackage grpc is deprecated.
io/ioutilPackage ioutil implements some I/O utility functions.
osPackage os provides a platform-independent interface to operating system functionality.