| context | Package context defines the Context type, which carries deadlines, cancellation signals, and other request-scoped values across API boundaries and between processes. |
| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| github.com/coreos/etcd/etcdserver/etcdserverpb | Package etcdserverpb is a generated protocol buffer package. |
| google.golang.org/grpc | Package grpc implements an RPC system called gRPC. |
| google.golang.org/grpc/resolver | Package resolver defines APIs for name resolution in gRPC. |
| io/ioutil | Package ioutil implements some I/O utility functions. |
| net | Package net provides a portable interface for network I/O, including TCP/IP, UDP, domain name resolution, and Unix domain sockets. |
| os | Package os provides a platform-independent interface to operating system functionality. |
| sync | Package sync provides basic synchronization primitives such as mutual exclusion locks. |