| context | Package context defines the Context type, which carries deadlines, cancellation signals, and other request-scoped values across API boundaries and between processes. |
| github.com/golang/protobuf/proto | Package proto provides functionality for handling protocol buffer messages. |
| google.golang.org/appengine/internal | Package internal provides support for package appengine. |
| google.golang.org/appengine/internal/user | |
| strings | Package strings implements simple functions to manipulate UTF-8 encoded strings. |