clientv3: update error handling godoc
//
// 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
+// })
+// if err == grpc.ErrClientConnTimeout {
+// // handle errors
+// }
+//
// cli, err := clientv3.New(clientv3.Config{
// Endpoints: []string{"localhost:2379", "localhost:22379", "localhost:32379"},
// DialTimeout: 5 * time.Second,
// 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 2 types of errors:
+// etcd client returns 3 types of errors:
//
// 1. context error: canceled or deadline exceeded.
-// 2. gRPC error: see https://github.com/coreos/etcd/blob/master/etcdserver/api/v3rpc/rpctypes/error.go
+// 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:
//
// }
// }
//
+// 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
