| errors | Package errors implements functions to manipulate errors. |
| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| google.golang.org/grpc/grpclog | Package grpclog defines logging for grpc. |
| google.golang.org/grpc/internal/grpclog | Package grpclog provides logging functionality for internal gRPC packages, outside of the functionality provided by the external `grpclog` package. |
| io | Package io provides basic interfaces to I/O primitives. |
| io/ioutil | Package ioutil implements some I/O utility functions. |
| os | Package os provides a platform-independent interface to operating system functionality. |
| os/exec | Package exec runs external commands. |
| regexp | Package regexp implements regular expression search. |
| runtime | Package runtime contains operations that interact with Go's runtime system, such as functions to control goroutines. |
| strings | Package strings implements simple functions to manipulate UTF-8 encoded strings. |
| sync | Package sync provides basic synchronization primitives such as mutual exclusion locks. |