code: func Is(err error) bool {
  	return err == context.Canceled || grpc.Code(err) == codes.Canceled
  }
docs: // Is returns true if err is non-nil and is either context.Canceled, or has a
  // grpc code of Canceled. This is useful because cancelations propagate through
  // gRPC boundaries, and if we choose to treat in-process cancellations a certain
  // way, we usually want to treat cross-process cancellations the same way.