Question: I'm trying to use `google/protobuf/timestamp.proto` in with gRPC plugin and Go. This is how I run `protoc`:

```
protoc -I  ./   ./*.proto --go_out=plugins=grpc:.

```

And this is my `.proto`:

```
#domain.proto
syntax = "proto3";
option java_multiple_files = true;
option java_package = "com.viant.xyz";
option java_outer_classname = "domain";

import "google/protobuf/timestamp.proto";

message Foo {
    Timestamp modifiedTime = 1;
    ...
}

```

I'm seeing the following errors:

```
domain.proto: Import "google/protobuf/timestamp.proto" was not found or had errors.
domain.proto:44:5: "Timestamp" is not defined.

```

Am I missing something, or this is not yet supported?

Answer: 
It is not fully supported yet, but you can make it work by changing

```
message Foo {
    google.protobuf.Timestamp modifiedTime = 1;
    ...
}

```

and by fixing generated file import

```
import google_protobuf "google/protobuf/timestamp.pb"

```

to

```
import google_protobuf "github.com/golang/protobuf/ptypes/timestamp"

```
I work around the problem by passing a `Mgoogle/protobuf/timestamp.proto=github.com/golang/protobuf/ptypes/timestamp` option to the Go grpc plugin.

In other words, I'm calling

```
protoc --go_out=plugins=grpc,Mgoogle/protobuf/timestamp.proto=github.com/golang/protobuf/ptypes/timestamp:outputdir input.proto

```

It's a bit of a hack. "Fortunately" I'm already using lots of `Mprotofile=go/pkg/import/path` parameters in my build setup, so it was easy to add.