[VOL-4291] Rw-core updates for gRPC migration
Change-Id: I8d5a554409115b29318089671ca4e1ab3fa98810
diff --git a/vendor/github.com/coreos/etcd/clientv3/doc.go b/vendor/github.com/coreos/etcd/clientv3/doc.go
new file mode 100644
index 0000000..717fbe4
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/clientv3/doc.go
@@ -0,0 +1,97 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package clientv3 implements the official Go etcd client for v3.
+//
+// Create client using `clientv3.New`:
+//
+// // expect dial time-out on ipv4 blackhole
+// _, err := clientv3.New(clientv3.Config{
+// Endpoints: []string{"http://254.0.0.1:12345"},
+// DialTimeout: 2 * time.Second
+// })
+//
+// // etcd clientv3 >= v3.2.10, grpc/grpc-go >= v1.7.3
+// if err == context.DeadlineExceeded {
+// // handle errors
+// }
+//
+// // etcd clientv3 <= v3.2.9, grpc/grpc-go <= v1.2.1
+// if err == grpc.ErrClientConnTimeout {
+// // handle errors
+// }
+//
+// cli, err := clientv3.New(clientv3.Config{
+// Endpoints: []string{"localhost:2379", "localhost:22379", "localhost:32379"},
+// DialTimeout: 5 * time.Second,
+// })
+// if err != nil {
+// // handle error!
+// }
+// defer cli.Close()
+//
+// Make sure to close the client after using it. If the client is not closed, the
+// connection will have leaky goroutines.
+//
+// To specify a client request timeout, wrap the context with context.WithTimeout:
+//
+// ctx, cancel := context.WithTimeout(context.Background(), timeout)
+// resp, err := kvc.Put(ctx, "sample_key", "sample_value")
+// cancel()
+// if err != nil {
+// // handle error!
+// }
+// // use the response
+//
+// The Client has internal state (watchers and leases), so Clients should be reused instead of created as needed.
+// Clients are safe for concurrent use by multiple goroutines.
+//
+// etcd client returns 3 types of errors:
+//
+// 1. context error: canceled or deadline exceeded.
+// 2. gRPC status error: e.g. when clock drifts in server-side before client's context deadline exceeded.
+// 3. gRPC error: see https://github.com/coreos/etcd/blob/master/etcdserver/api/v3rpc/rpctypes/error.go
+//
+// Here is the example code to handle client errors:
+//
+// resp, err := kvc.Put(ctx, "", "")
+// if err != nil {
+// if err == context.Canceled {
+// // ctx is canceled by another routine
+// } else if err == context.DeadlineExceeded {
+// // ctx is attached with a deadline and it exceeded
+// } else if ev, ok := status.FromError(err); ok {
+// code := ev.Code()
+// if code == codes.DeadlineExceeded {
+// // server-side context might have timed-out first (due to clock skew)
+// // while original client-side context is not timed-out yet
+// }
+// } else if verr, ok := err.(*v3rpc.ErrEmptyKey); ok {
+// // process (verr.Errors)
+// } else {
+// // bad cluster endpoints, which are not etcd servers
+// }
+// }
+//
+// go func() { cli.Close() }()
+// _, err := kvc.Get(ctx, "a")
+// if err != nil {
+// if err == context.Canceled {
+// // grpc balancer calls 'Get' with an inflight client.Close
+// } else if err == grpc.ErrClientConnClosing {
+// // grpc balancer calls 'Get' after client.Close.
+// }
+// }
+//
+package clientv3