| errors | Package errors implements functions to manipulate errors. |
| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| golang.org/x/net/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 | Package grpc implements an RPC system called gRPC. |
| google.golang.org/grpc/codes | Package codes defines the canonical error codes used by gRPC. |
| google.golang.org/grpc/credentials | Package credentials implements various credentials supported by gRPC library, which encapsulate all the state needed by a client to authenticate with a server and make various assertions, e.g., about the client's identity, role, or whether it is authorized to make a particular call. |
| google.golang.org/grpc/credentials/alts/core | |
| google.golang.org/grpc/credentials/alts/core/authinfo | |
| google.golang.org/grpc/credentials/alts/core/conn | |
| google.golang.org/grpc/credentials/alts/core/proto/grpc_gcp | |
| io | Package io provides basic interfaces to I/O primitives. |
| net | Package net provides a portable interface for network I/O, including TCP/IP, UDP, domain name resolution, and Unix domain sockets. |
| sync | Package sync provides basic synchronization primitives such as mutual exclusion locks. |