Imports of package cache

PathSynopsis
errorsPackage errors implements functions to manipulate errors.
github.com/coreos/etcd/etcdserver/api/v3rpc/rpctypes
github.com/coreos/etcd/etcdserver/etcdserverpbPackage etcdserverpb is a generated protocol buffer package.
github.com/coreos/etcd/pkg/adt
github.com/karlseguin/ccache
syncPackage sync provides basic synchronization primitives such as mutual exclusion locks.
timePackage time provides functionality for measuring and displaying time.