| errors | Package errors implements functions to manipulate errors. |
| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| github.com/golang/protobuf/proto | Package proto provides functionality for handling protocol buffer messages. |
| github.com/golang/protobuf/ptypes | Package ptypes provides functionality for interacting with well-known types. |
| google.golang.org/genproto/googleapis/rpc/status | |
| google.golang.org/grpc/codes | Package codes defines the canonical error codes used by gRPC. |