"google.protobuf.Timestamp" is not defined, compiling from Grpc.Tools 1.6.1 · Issue #12814 · grpc/grpc

I'm using Visual Studio 2017 Professional, with the following dependencies: <PackageReference Include="Google.Protobuf" Version="3.4.1" /> <PackageReference Include="Grpc" Version="1.6.1" /> </packagereference></packagereference>