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