| context | Package context defines the Context type, which carries deadlines, cancellation signals, and other request-scoped values across API boundaries and between processes. |
| google.golang.org/grpc/internal/serviceconfig | Package serviceconfig contains utility functions to parse service config. |
| google.golang.org/grpc/metadata | Package metadata define the structure of the metadata supported by gRPC library. |
| google.golang.org/grpc/resolver | Package resolver defines APIs for name resolution in gRPC. |
| sync | Package sync provides basic synchronization primitives such as mutual exclusion locks. |