diff --git a/vendor/go.etcd.io/etcd/clientv3/balancer/balancer.go b/vendor/go.etcd.io/etcd/clientv3/balancer/balancer.go
index c39702e..d02a7ee 100644
--- a/vendor/go.etcd.io/etcd/clientv3/balancer/balancer.go
+++ b/vendor/go.etcd.io/etcd/clientv3/balancer/balancer.go
@@ -12,24 +12,45 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// Package balancer implements client balancer.
 package balancer
 
 import (
-	"fmt"
 	"strconv"
 	"sync"
 	"time"
 
+	"go.etcd.io/etcd/clientv3/balancer/connectivity"
 	"go.etcd.io/etcd/clientv3/balancer/picker"
 
 	"go.uber.org/zap"
 	"google.golang.org/grpc/balancer"
-	"google.golang.org/grpc/connectivity"
+	grpcconnectivity "google.golang.org/grpc/connectivity"
 	"google.golang.org/grpc/resolver"
 	_ "google.golang.org/grpc/resolver/dns"         // register DNS resolver
 	_ "google.golang.org/grpc/resolver/passthrough" // register passthrough resolver
 )
 
+// Config defines balancer configurations.
+type Config struct {
+	// Policy configures balancer policy.
+	Policy picker.Policy
+
+	// Picker implements gRPC picker.
+	// Leave empty if "Policy" field is not custom.
+	// TODO: currently custom policy is not supported.
+	// Picker picker.Picker
+
+	// Name defines an additional name for balancer.
+	// Useful for balancer testing to avoid register conflicts.
+	// If empty, defaults to policy name.
+	Name string
+
+	// Logger configures balancer logging.
+	// If nil, logs are discarded.
+	Logger *zap.Logger
+}
+
 // RegisterBuilder creates and registers a builder. Since this function calls balancer.Register, it
 // must be invoked at initialization time.
 func RegisterBuilder(cfg Config) {
@@ -59,16 +80,13 @@
 
 		addrToSc: make(map[resolver.Address]balancer.SubConn),
 		scToAddr: make(map[balancer.SubConn]resolver.Address),
-		scToSt:   make(map[balancer.SubConn]connectivity.State),
+		scToSt:   make(map[balancer.SubConn]grpcconnectivity.State),
 
-		currentConn: nil,
-		csEvltr:     &connectivityStateEvaluator{},
+		currentConn:          nil,
+		connectivityRecorder: connectivity.New(b.cfg.Logger),
 
 		// initialize picker always returns "ErrNoSubConnAvailable"
-		Picker: picker.NewErr(balancer.ErrNoSubConnAvailable),
-	}
-	if bb.lg == nil {
-		bb.lg = zap.NewNop()
+		picker: picker.NewErr(balancer.ErrNoSubConnAvailable),
 	}
 
 	// TODO: support multiple connections
@@ -112,13 +130,12 @@
 
 	addrToSc map[resolver.Address]balancer.SubConn
 	scToAddr map[balancer.SubConn]resolver.Address
-	scToSt   map[balancer.SubConn]connectivity.State
+	scToSt   map[balancer.SubConn]grpcconnectivity.State
 
-	currentConn  balancer.ClientConn
-	currentState connectivity.State
-	csEvltr      *connectivityStateEvaluator
+	currentConn          balancer.ClientConn
+	connectivityRecorder connectivity.Recorder
 
-	picker.Picker
+	picker picker.Picker
 }
 
 // HandleResolvedAddrs implements "grpc/balancer.Balancer" interface.
@@ -128,7 +145,11 @@
 		bb.lg.Warn("HandleResolvedAddrs called with error", zap.String("balancer-id", bb.id), zap.Error(err))
 		return
 	}
-	bb.lg.Info("resolved", zap.String("balancer-id", bb.id), zap.Strings("addresses", addrsToStrings(addrs)))
+	bb.lg.Info("resolved",
+		zap.String("picker", bb.picker.String()),
+		zap.String("balancer-id", bb.id),
+		zap.Strings("addresses", addrsToStrings(addrs)),
+	)
 
 	bb.mu.Lock()
 	defer bb.mu.Unlock()
@@ -139,12 +160,13 @@
 		if _, ok := bb.addrToSc[addr]; !ok {
 			sc, err := bb.currentConn.NewSubConn([]resolver.Address{addr}, balancer.NewSubConnOptions{})
 			if err != nil {
-				bb.lg.Warn("NewSubConn failed", zap.String("balancer-id", bb.id), zap.Error(err), zap.String("address", addr.Addr))
+				bb.lg.Warn("NewSubConn failed", zap.String("picker", bb.picker.String()), zap.String("balancer-id", bb.id), zap.Error(err), zap.String("address", addr.Addr))
 				continue
 			}
+			bb.lg.Info("created subconn", zap.String("address", addr.Addr))
 			bb.addrToSc[addr] = sc
 			bb.scToAddr[sc] = addr
-			bb.scToSt[sc] = connectivity.Idle
+			bb.scToSt[sc] = grpcconnectivity.Idle
 			sc.Connect()
 		}
 	}
@@ -157,6 +179,7 @@
 
 			bb.lg.Info(
 				"removed subconn",
+				zap.String("picker", bb.picker.String()),
 				zap.String("balancer-id", bb.id),
 				zap.String("address", addr.Addr),
 				zap.String("subconn", scToString(sc)),
@@ -171,7 +194,7 @@
 }
 
 // HandleSubConnStateChange implements "grpc/balancer.Balancer" interface.
-func (bb *baseBalancer) HandleSubConnStateChange(sc balancer.SubConn, s connectivity.State) {
+func (bb *baseBalancer) HandleSubConnStateChange(sc balancer.SubConn, s grpcconnectivity.State) {
 	bb.mu.Lock()
 	defer bb.mu.Unlock()
 
@@ -179,8 +202,10 @@
 	if !ok {
 		bb.lg.Warn(
 			"state change for an unknown subconn",
+			zap.String("picker", bb.picker.String()),
 			zap.String("balancer-id", bb.id),
 			zap.String("subconn", scToString(sc)),
+			zap.Int("subconn-size", len(bb.scToAddr)),
 			zap.String("state", s.String()),
 		)
 		return
@@ -188,9 +213,11 @@
 
 	bb.lg.Info(
 		"state changed",
+		zap.String("picker", bb.picker.String()),
 		zap.String("balancer-id", bb.id),
-		zap.Bool("connected", s == connectivity.Ready),
+		zap.Bool("connected", s == grpcconnectivity.Ready),
 		zap.String("subconn", scToString(sc)),
+		zap.Int("subconn-size", len(bb.scToAddr)),
 		zap.String("address", bb.scToAddr[sc].Addr),
 		zap.String("old-state", old.String()),
 		zap.String("new-state", s.String()),
@@ -198,68 +225,63 @@
 
 	bb.scToSt[sc] = s
 	switch s {
-	case connectivity.Idle:
+	case grpcconnectivity.Idle:
 		sc.Connect()
-	case connectivity.Shutdown:
+	case grpcconnectivity.Shutdown:
 		// When an address was removed by resolver, b called RemoveSubConn but
 		// kept the sc's state in scToSt. Remove state for this sc here.
 		delete(bb.scToAddr, sc)
 		delete(bb.scToSt, sc)
 	}
 
-	oldAggrState := bb.currentState
-	bb.currentState = bb.csEvltr.recordTransition(old, s)
+	oldAggrState := bb.connectivityRecorder.GetCurrentState()
+	bb.connectivityRecorder.RecordTransition(old, s)
 
-	// Regenerate picker when one of the following happens:
+	// Update balancer picker when one of the following happens:
 	//  - this sc became ready from not-ready
 	//  - this sc became not-ready from ready
 	//  - the aggregated state of balancer became TransientFailure from non-TransientFailure
 	//  - the aggregated state of balancer became non-TransientFailure from TransientFailure
-	if (s == connectivity.Ready) != (old == connectivity.Ready) ||
-		(bb.currentState == connectivity.TransientFailure) != (oldAggrState == connectivity.TransientFailure) {
-		bb.regeneratePicker()
+	if (s == grpcconnectivity.Ready) != (old == grpcconnectivity.Ready) ||
+		(bb.connectivityRecorder.GetCurrentState() == grpcconnectivity.TransientFailure) != (oldAggrState == grpcconnectivity.TransientFailure) {
+		bb.updatePicker()
 	}
 
-	bb.currentConn.UpdateBalancerState(bb.currentState, bb.Picker)
+	bb.currentConn.UpdateBalancerState(bb.connectivityRecorder.GetCurrentState(), bb.picker)
 }
 
-func (bb *baseBalancer) regeneratePicker() {
-	if bb.currentState == connectivity.TransientFailure {
+func (bb *baseBalancer) updatePicker() {
+	if bb.connectivityRecorder.GetCurrentState() == grpcconnectivity.TransientFailure {
+		bb.picker = picker.NewErr(balancer.ErrTransientFailure)
 		bb.lg.Info(
-			"generated transient error picker",
+			"updated picker to transient error picker",
+			zap.String("picker", bb.picker.String()),
 			zap.String("balancer-id", bb.id),
 			zap.String("policy", bb.policy.String()),
 		)
-		bb.Picker = picker.NewErr(balancer.ErrTransientFailure)
 		return
 	}
 
 	// only pass ready subconns to picker
-	scs := make([]balancer.SubConn, 0)
-	addrToSc := make(map[resolver.Address]balancer.SubConn)
 	scToAddr := make(map[balancer.SubConn]resolver.Address)
 	for addr, sc := range bb.addrToSc {
-		if st, ok := bb.scToSt[sc]; ok && st == connectivity.Ready {
-			scs = append(scs, sc)
-			addrToSc[addr] = sc
+		if st, ok := bb.scToSt[sc]; ok && st == grpcconnectivity.Ready {
 			scToAddr[sc] = addr
 		}
 	}
 
-	switch bb.policy {
-	case picker.RoundrobinBalanced:
-		bb.Picker = picker.NewRoundrobinBalanced(bb.lg, scs, addrToSc, scToAddr)
-
-	default:
-		panic(fmt.Errorf("invalid balancer picker policy (%d)", bb.policy))
-	}
-
+	bb.picker = picker.New(picker.Config{
+		Policy:                   bb.policy,
+		Logger:                   bb.lg,
+		SubConnToResolverAddress: scToAddr,
+	})
 	bb.lg.Info(
-		"generated picker",
+		"updated picker",
+		zap.String("picker", bb.picker.String()),
 		zap.String("balancer-id", bb.id),
 		zap.String("policy", bb.policy.String()),
-		zap.Strings("subconn-ready", scsToStrings(addrToSc)),
-		zap.Int("subconn-size", len(addrToSc)),
+		zap.Strings("subconn-ready", scsToStrings(scToAddr)),
+		zap.Int("subconn-size", len(scToAddr)),
 	)
 }
 
diff --git a/vendor/go.etcd.io/etcd/clientv3/balancer/config.go b/vendor/go.etcd.io/etcd/clientv3/balancer/config.go
deleted file mode 100644
index 0339a84..0000000
--- a/vendor/go.etcd.io/etcd/clientv3/balancer/config.go
+++ /dev/null
@@ -1,36 +0,0 @@
-// Copyright 2018 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 balancer
-
-import (
-	"go.etcd.io/etcd/clientv3/balancer/picker"
-
-	"go.uber.org/zap"
-)
-
-// Config defines balancer configurations.
-type Config struct {
-	// Policy configures balancer policy.
-	Policy picker.Policy
-
-	// Name defines an additional name for balancer.
-	// Useful for balancer testing to avoid register conflicts.
-	// If empty, defaults to policy name.
-	Name string
-
-	// Logger configures balancer logging.
-	// If nil, logs are discarded.
-	Logger *zap.Logger
-}
diff --git a/vendor/go.etcd.io/etcd/clientv3/balancer/connectivity.go b/vendor/go.etcd.io/etcd/clientv3/balancer/connectivity.go
deleted file mode 100644
index 6cdeb3f..0000000
--- a/vendor/go.etcd.io/etcd/clientv3/balancer/connectivity.go
+++ /dev/null
@@ -1,58 +0,0 @@
-// Copyright 2018 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 balancer
-
-import "google.golang.org/grpc/connectivity"
-
-// connectivityStateEvaluator gets updated by addrConns when their
-// states transition, based on which it evaluates the state of
-// ClientConn.
-type connectivityStateEvaluator struct {
-	numReady            uint64 // Number of addrConns in ready state.
-	numConnecting       uint64 // Number of addrConns in connecting state.
-	numTransientFailure uint64 // Number of addrConns in transientFailure.
-}
-
-// recordTransition records state change happening in every subConn and based on
-// that it evaluates what aggregated state should be.
-// It can only transition between Ready, Connecting and TransientFailure. Other states,
-// Idle and Shutdown are transitioned into by ClientConn; in the beginning of the connection
-// before any subConn is created ClientConn is in idle state. In the end when ClientConn
-// closes it is in Shutdown state.
-//
-// recordTransition should only be called synchronously from the same goroutine.
-func (cse *connectivityStateEvaluator) recordTransition(oldState, newState connectivity.State) connectivity.State {
-	// Update counters.
-	for idx, state := range []connectivity.State{oldState, newState} {
-		updateVal := 2*uint64(idx) - 1 // -1 for oldState and +1 for new.
-		switch state {
-		case connectivity.Ready:
-			cse.numReady += updateVal
-		case connectivity.Connecting:
-			cse.numConnecting += updateVal
-		case connectivity.TransientFailure:
-			cse.numTransientFailure += updateVal
-		}
-	}
-
-	// Evaluate.
-	if cse.numReady > 0 {
-		return connectivity.Ready
-	}
-	if cse.numConnecting > 0 {
-		return connectivity.Connecting
-	}
-	return connectivity.TransientFailure
-}
diff --git a/vendor/go.etcd.io/etcd/clientv3/balancer/connectivity/connectivity.go b/vendor/go.etcd.io/etcd/clientv3/balancer/connectivity/connectivity.go
new file mode 100644
index 0000000..4c4ad36
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/clientv3/balancer/connectivity/connectivity.go
@@ -0,0 +1,93 @@
+// Copyright 2019 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 connectivity implements client connectivity operations.
+package connectivity
+
+import (
+	"sync"
+
+	"go.uber.org/zap"
+	"google.golang.org/grpc/connectivity"
+)
+
+// Recorder records gRPC connectivity.
+type Recorder interface {
+	GetCurrentState() connectivity.State
+	RecordTransition(oldState, newState connectivity.State)
+}
+
+// New returns a new Recorder.
+func New(lg *zap.Logger) Recorder {
+	return &recorder{lg: lg}
+}
+
+// recorder takes the connectivity states of multiple SubConns
+// and returns one aggregated connectivity state.
+// ref. https://github.com/grpc/grpc-go/blob/master/balancer/balancer.go
+type recorder struct {
+	lg *zap.Logger
+
+	mu sync.RWMutex
+
+	cur connectivity.State
+
+	numReady            uint64 // Number of addrConns in ready state.
+	numConnecting       uint64 // Number of addrConns in connecting state.
+	numTransientFailure uint64 // Number of addrConns in transientFailure.
+}
+
+func (rc *recorder) GetCurrentState() (state connectivity.State) {
+	rc.mu.RLock()
+	defer rc.mu.RUnlock()
+	return rc.cur
+}
+
+// RecordTransition records state change happening in subConn and based on that
+// it evaluates what aggregated state should be.
+//
+//  - If at least one SubConn in Ready, the aggregated state is Ready;
+//  - Else if at least one SubConn in Connecting, the aggregated state is Connecting;
+//  - Else the aggregated state is TransientFailure.
+//
+// Idle and Shutdown are not considered.
+//
+// ref. https://github.com/grpc/grpc-go/blob/master/balancer/balancer.go
+func (rc *recorder) RecordTransition(oldState, newState connectivity.State) {
+	rc.mu.Lock()
+	defer rc.mu.Unlock()
+
+	for idx, state := range []connectivity.State{oldState, newState} {
+		updateVal := 2*uint64(idx) - 1 // -1 for oldState and +1 for new.
+		switch state {
+		case connectivity.Ready:
+			rc.numReady += updateVal
+		case connectivity.Connecting:
+			rc.numConnecting += updateVal
+		case connectivity.TransientFailure:
+			rc.numTransientFailure += updateVal
+		default:
+			rc.lg.Warn("connectivity recorder received unknown state", zap.String("connectivity-state", state.String()))
+		}
+	}
+
+	switch { // must be exclusive, no overlap
+	case rc.numReady > 0:
+		rc.cur = connectivity.Ready
+	case rc.numConnecting > 0:
+		rc.cur = connectivity.Connecting
+	default:
+		rc.cur = connectivity.TransientFailure
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/clientv3/balancer/doc.go b/vendor/go.etcd.io/etcd/clientv3/balancer/doc.go
deleted file mode 100644
index 45af5e9..0000000
--- a/vendor/go.etcd.io/etcd/clientv3/balancer/doc.go
+++ /dev/null
@@ -1,16 +0,0 @@
-// Copyright 2018 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 balancer implements client balancer.
-package balancer
diff --git a/vendor/go.etcd.io/etcd/clientv3/balancer/grpc1.7-health.go b/vendor/go.etcd.io/etcd/clientv3/balancer/grpc1.7-health.go
deleted file mode 100644
index 2153767..0000000
--- a/vendor/go.etcd.io/etcd/clientv3/balancer/grpc1.7-health.go
+++ /dev/null
@@ -1,657 +0,0 @@
-// Copyright 2018 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 balancer
-
-import (
-	"context"
-	"errors"
-	"io/ioutil"
-	"net/url"
-	"strings"
-	"sync"
-	"time"
-
-	"google.golang.org/grpc"
-	"google.golang.org/grpc/codes"
-	"google.golang.org/grpc/grpclog"
-	healthpb "google.golang.org/grpc/health/grpc_health_v1"
-	"google.golang.org/grpc/status"
-)
-
-// TODO: replace with something better
-var lg = grpclog.NewLoggerV2(ioutil.Discard, ioutil.Discard, ioutil.Discard)
-
-const (
-	minHealthRetryDuration = 3 * time.Second
-	unknownService         = "unknown service grpc.health.v1.Health"
-)
-
-// ErrNoAddrAvailable is returned by Get() when the balancer does not have
-// any active connection to endpoints at the time.
-// This error is returned only when opts.BlockingWait is true.
-var ErrNoAddrAvailable = status.Error(codes.Unavailable, "there is no address available")
-
-type NotifyMsg int
-
-const (
-	NotifyReset NotifyMsg = iota
-	NotifyNext
-)
-
-// GRPC17Health does the bare minimum to expose multiple eps
-// to the grpc reconnection code path
-type GRPC17Health struct {
-	// addrs are the client's endpoint addresses for grpc
-	addrs []grpc.Address
-
-	// eps holds the raw endpoints from the client
-	eps []string
-
-	// notifyCh notifies grpc of the set of addresses for connecting
-	notifyCh chan []grpc.Address
-
-	// readyc closes once the first connection is up
-	readyc    chan struct{}
-	readyOnce sync.Once
-
-	// healthCheck checks an endpoint's health.
-	healthCheck        func(ep string) (bool, error)
-	healthCheckTimeout time.Duration
-
-	unhealthyMu        sync.RWMutex
-	unhealthyHostPorts map[string]time.Time
-
-	// mu protects all fields below.
-	mu sync.RWMutex
-
-	// upc closes when pinAddr transitions from empty to non-empty or the balancer closes.
-	upc chan struct{}
-
-	// downc closes when grpc calls down() on pinAddr
-	downc chan struct{}
-
-	// stopc is closed to signal updateNotifyLoop should stop.
-	stopc    chan struct{}
-	stopOnce sync.Once
-	wg       sync.WaitGroup
-
-	// donec closes when all goroutines are exited
-	donec chan struct{}
-
-	// updateAddrsC notifies updateNotifyLoop to update addrs.
-	updateAddrsC chan NotifyMsg
-
-	// grpc issues TLS cert checks using the string passed into dial so
-	// that string must be the host. To recover the full scheme://host URL,
-	// have a map from hosts to the original endpoint.
-	hostPort2ep map[string]string
-
-	// pinAddr is the currently pinned address; set to the empty string on
-	// initialization and shutdown.
-	pinAddr string
-
-	closed bool
-}
-
-// DialFunc defines gRPC dial function.
-type DialFunc func(ep string, dopts ...grpc.DialOption) (*grpc.ClientConn, error)
-
-// NewGRPC17Health returns a new health balancer with gRPC v1.7.
-func NewGRPC17Health(
-	eps []string,
-	timeout time.Duration,
-	dialFunc DialFunc,
-) *GRPC17Health {
-	notifyCh := make(chan []grpc.Address)
-	addrs := eps2addrs(eps)
-	hb := &GRPC17Health{
-		addrs:              addrs,
-		eps:                eps,
-		notifyCh:           notifyCh,
-		readyc:             make(chan struct{}),
-		healthCheck:        func(ep string) (bool, error) { return grpcHealthCheck(ep, dialFunc) },
-		unhealthyHostPorts: make(map[string]time.Time),
-		upc:                make(chan struct{}),
-		stopc:              make(chan struct{}),
-		downc:              make(chan struct{}),
-		donec:              make(chan struct{}),
-		updateAddrsC:       make(chan NotifyMsg),
-		hostPort2ep:        getHostPort2ep(eps),
-	}
-	if timeout < minHealthRetryDuration {
-		timeout = minHealthRetryDuration
-	}
-	hb.healthCheckTimeout = timeout
-
-	close(hb.downc)
-	go hb.updateNotifyLoop()
-	hb.wg.Add(1)
-	go func() {
-		defer hb.wg.Done()
-		hb.updateUnhealthy()
-	}()
-	return hb
-}
-
-func (b *GRPC17Health) Start(target string, config grpc.BalancerConfig) error { return nil }
-
-func (b *GRPC17Health) ConnectNotify() <-chan struct{} {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-	return b.upc
-}
-
-func (b *GRPC17Health) UpdateAddrsC() chan NotifyMsg { return b.updateAddrsC }
-func (b *GRPC17Health) StopC() chan struct{}         { return b.stopc }
-
-func (b *GRPC17Health) Ready() <-chan struct{} { return b.readyc }
-
-func (b *GRPC17Health) Endpoint(hostPort string) string {
-	b.mu.RLock()
-	defer b.mu.RUnlock()
-	return b.hostPort2ep[hostPort]
-}
-
-func (b *GRPC17Health) Pinned() string {
-	b.mu.RLock()
-	defer b.mu.RUnlock()
-	return b.pinAddr
-}
-
-func (b *GRPC17Health) HostPortError(hostPort string, err error) {
-	if b.Endpoint(hostPort) == "" {
-		lg.Infof("clientv3/balancer: %q is stale (skip marking as unhealthy on %q)", hostPort, err.Error())
-		return
-	}
-
-	b.unhealthyMu.Lock()
-	b.unhealthyHostPorts[hostPort] = time.Now()
-	b.unhealthyMu.Unlock()
-	lg.Infof("clientv3/balancer: %q is marked unhealthy (%q)", hostPort, err.Error())
-}
-
-func (b *GRPC17Health) removeUnhealthy(hostPort, msg string) {
-	if b.Endpoint(hostPort) == "" {
-		lg.Infof("clientv3/balancer: %q was not in unhealthy (%q)", hostPort, msg)
-		return
-	}
-
-	b.unhealthyMu.Lock()
-	delete(b.unhealthyHostPorts, hostPort)
-	b.unhealthyMu.Unlock()
-	lg.Infof("clientv3/balancer: %q is removed from unhealthy (%q)", hostPort, msg)
-}
-
-func (b *GRPC17Health) countUnhealthy() (count int) {
-	b.unhealthyMu.RLock()
-	count = len(b.unhealthyHostPorts)
-	b.unhealthyMu.RUnlock()
-	return count
-}
-
-func (b *GRPC17Health) isUnhealthy(hostPort string) (unhealthy bool) {
-	b.unhealthyMu.RLock()
-	_, unhealthy = b.unhealthyHostPorts[hostPort]
-	b.unhealthyMu.RUnlock()
-	return unhealthy
-}
-
-func (b *GRPC17Health) cleanupUnhealthy() {
-	b.unhealthyMu.Lock()
-	for k, v := range b.unhealthyHostPorts {
-		if time.Since(v) > b.healthCheckTimeout {
-			delete(b.unhealthyHostPorts, k)
-			lg.Infof("clientv3/balancer: removed %q from unhealthy after %v", k, b.healthCheckTimeout)
-		}
-	}
-	b.unhealthyMu.Unlock()
-}
-
-func (b *GRPC17Health) liveAddrs() ([]grpc.Address, map[string]struct{}) {
-	unhealthyCnt := b.countUnhealthy()
-
-	b.mu.RLock()
-	defer b.mu.RUnlock()
-
-	hbAddrs := b.addrs
-	if len(b.addrs) == 1 || unhealthyCnt == 0 || unhealthyCnt == len(b.addrs) {
-		liveHostPorts := make(map[string]struct{}, len(b.hostPort2ep))
-		for k := range b.hostPort2ep {
-			liveHostPorts[k] = struct{}{}
-		}
-		return hbAddrs, liveHostPorts
-	}
-
-	addrs := make([]grpc.Address, 0, len(b.addrs)-unhealthyCnt)
-	liveHostPorts := make(map[string]struct{}, len(addrs))
-	for _, addr := range b.addrs {
-		if !b.isUnhealthy(addr.Addr) {
-			addrs = append(addrs, addr)
-			liveHostPorts[addr.Addr] = struct{}{}
-		}
-	}
-	return addrs, liveHostPorts
-}
-
-func (b *GRPC17Health) updateUnhealthy() {
-	for {
-		select {
-		case <-time.After(b.healthCheckTimeout):
-			b.cleanupUnhealthy()
-			pinned := b.Pinned()
-			if pinned == "" || b.isUnhealthy(pinned) {
-				select {
-				case b.updateAddrsC <- NotifyNext:
-				case <-b.stopc:
-					return
-				}
-			}
-		case <-b.stopc:
-			return
-		}
-	}
-}
-
-// NeedUpdate returns true if all connections are down or
-// addresses do not include current pinned address.
-func (b *GRPC17Health) NeedUpdate() bool {
-	// updating notifyCh can trigger new connections,
-	// need update addrs if all connections are down
-	// or addrs does not include pinAddr.
-	b.mu.RLock()
-	update := !hasAddr(b.addrs, b.pinAddr)
-	b.mu.RUnlock()
-	return update
-}
-
-func (b *GRPC17Health) UpdateAddrs(eps ...string) {
-	np := getHostPort2ep(eps)
-
-	b.mu.Lock()
-	defer b.mu.Unlock()
-
-	match := len(np) == len(b.hostPort2ep)
-	if match {
-		for k, v := range np {
-			if b.hostPort2ep[k] != v {
-				match = false
-				break
-			}
-		}
-	}
-	if match {
-		// same endpoints, so no need to update address
-		return
-	}
-
-	b.hostPort2ep = np
-	b.addrs, b.eps = eps2addrs(eps), eps
-
-	b.unhealthyMu.Lock()
-	b.unhealthyHostPorts = make(map[string]time.Time)
-	b.unhealthyMu.Unlock()
-}
-
-func (b *GRPC17Health) Next() {
-	b.mu.RLock()
-	downc := b.downc
-	b.mu.RUnlock()
-	select {
-	case b.updateAddrsC <- NotifyNext:
-	case <-b.stopc:
-	}
-	// wait until disconnect so new RPCs are not issued on old connection
-	select {
-	case <-downc:
-	case <-b.stopc:
-	}
-}
-
-func (b *GRPC17Health) updateNotifyLoop() {
-	defer close(b.donec)
-
-	for {
-		b.mu.RLock()
-		upc, downc, addr := b.upc, b.downc, b.pinAddr
-		b.mu.RUnlock()
-		// downc or upc should be closed
-		select {
-		case <-downc:
-			downc = nil
-		default:
-		}
-		select {
-		case <-upc:
-			upc = nil
-		default:
-		}
-		switch {
-		case downc == nil && upc == nil:
-			// stale
-			select {
-			case <-b.stopc:
-				return
-			default:
-			}
-		case downc == nil:
-			b.notifyAddrs(NotifyReset)
-			select {
-			case <-upc:
-			case msg := <-b.updateAddrsC:
-				b.notifyAddrs(msg)
-			case <-b.stopc:
-				return
-			}
-		case upc == nil:
-			select {
-			// close connections that are not the pinned address
-			case b.notifyCh <- []grpc.Address{{Addr: addr}}:
-			case <-downc:
-			case <-b.stopc:
-				return
-			}
-			select {
-			case <-downc:
-				b.notifyAddrs(NotifyReset)
-			case msg := <-b.updateAddrsC:
-				b.notifyAddrs(msg)
-			case <-b.stopc:
-				return
-			}
-		}
-	}
-}
-
-func (b *GRPC17Health) notifyAddrs(msg NotifyMsg) {
-	if msg == NotifyNext {
-		select {
-		case b.notifyCh <- []grpc.Address{}:
-		case <-b.stopc:
-			return
-		}
-	}
-	b.mu.RLock()
-	pinAddr := b.pinAddr
-	downc := b.downc
-	b.mu.RUnlock()
-	addrs, hostPorts := b.liveAddrs()
-
-	var waitDown bool
-	if pinAddr != "" {
-		_, ok := hostPorts[pinAddr]
-		waitDown = !ok
-	}
-
-	select {
-	case b.notifyCh <- addrs:
-		if waitDown {
-			select {
-			case <-downc:
-			case <-b.stopc:
-			}
-		}
-	case <-b.stopc:
-	}
-}
-
-func (b *GRPC17Health) Up(addr grpc.Address) func(error) {
-	if !b.mayPin(addr) {
-		return func(err error) {}
-	}
-
-	b.mu.Lock()
-	defer b.mu.Unlock()
-
-	// gRPC might call Up after it called Close. We add this check
-	// to "fix" it up at application layer. Otherwise, will panic
-	// if b.upc is already closed.
-	if b.closed {
-		return func(err error) {}
-	}
-
-	// gRPC might call Up on a stale address.
-	// Prevent updating pinAddr with a stale address.
-	if !hasAddr(b.addrs, addr.Addr) {
-		return func(err error) {}
-	}
-
-	if b.pinAddr != "" {
-		lg.Infof("clientv3/balancer: %q is up but not pinned (already pinned %q)", addr.Addr, b.pinAddr)
-		return func(err error) {}
-	}
-
-	// notify waiting Get()s and pin first connected address
-	close(b.upc)
-	b.downc = make(chan struct{})
-	b.pinAddr = addr.Addr
-	lg.Infof("clientv3/balancer: pin %q", addr.Addr)
-
-	// notify client that a connection is up
-	b.readyOnce.Do(func() { close(b.readyc) })
-
-	return func(err error) {
-		// If connected to a black hole endpoint or a killed server, the gRPC ping
-		// timeout will induce a network I/O error, and retrying until success;
-		// finding healthy endpoint on retry could take several timeouts and redials.
-		// To avoid wasting retries, gray-list unhealthy endpoints.
-		b.HostPortError(addr.Addr, err)
-
-		b.mu.Lock()
-		b.upc = make(chan struct{})
-		close(b.downc)
-		b.pinAddr = ""
-		b.mu.Unlock()
-		lg.Infof("clientv3/balancer: unpin %q (%q)", addr.Addr, err.Error())
-	}
-}
-
-func (b *GRPC17Health) mayPin(addr grpc.Address) bool {
-	if b.Endpoint(addr.Addr) == "" { // stale host:port
-		return false
-	}
-
-	b.unhealthyMu.RLock()
-	unhealthyCnt := len(b.unhealthyHostPorts)
-	failedTime, bad := b.unhealthyHostPorts[addr.Addr]
-	b.unhealthyMu.RUnlock()
-
-	b.mu.RLock()
-	skip := len(b.addrs) == 1 || unhealthyCnt == 0 || len(b.addrs) == unhealthyCnt
-	b.mu.RUnlock()
-	if skip || !bad {
-		return true
-	}
-
-	// prevent isolated member's endpoint from being infinitely retried, as follows:
-	//   1. keepalive pings detects GoAway with http2.ErrCodeEnhanceYourCalm
-	//   2. balancer 'Up' unpins with grpc: failed with network I/O error
-	//   3. grpc-healthcheck still SERVING, thus retry to pin
-	// instead, return before grpc-healthcheck if failed within healthcheck timeout
-	if elapsed := time.Since(failedTime); elapsed < b.healthCheckTimeout {
-		lg.Infof("clientv3/balancer: %q is up but not pinned (failed %v ago, require minimum %v after failure)", addr.Addr, elapsed, b.healthCheckTimeout)
-		return false
-	}
-
-	if ok, _ := b.healthCheck(addr.Addr); ok {
-		b.removeUnhealthy(addr.Addr, "health check success")
-		return true
-	}
-
-	b.HostPortError(addr.Addr, errors.New("health check failed"))
-	return false
-}
-
-func (b *GRPC17Health) Get(ctx context.Context, opts grpc.BalancerGetOptions) (grpc.Address, func(), error) {
-	var (
-		addr   string
-		closed bool
-	)
-
-	// If opts.BlockingWait is false (for fail-fast RPCs), it should return
-	// an address it has notified via Notify immediately instead of blocking.
-	if !opts.BlockingWait {
-		b.mu.RLock()
-		closed = b.closed
-		addr = b.pinAddr
-		b.mu.RUnlock()
-		if closed {
-			return grpc.Address{Addr: ""}, nil, grpc.ErrClientConnClosing
-		}
-		if addr == "" {
-			return grpc.Address{Addr: ""}, nil, ErrNoAddrAvailable
-		}
-		return grpc.Address{Addr: addr}, func() {}, nil
-	}
-
-	for {
-		b.mu.RLock()
-		ch := b.upc
-		b.mu.RUnlock()
-		select {
-		case <-ch:
-		case <-b.donec:
-			return grpc.Address{Addr: ""}, nil, grpc.ErrClientConnClosing
-		case <-ctx.Done():
-			return grpc.Address{Addr: ""}, nil, ctx.Err()
-		}
-		b.mu.RLock()
-		closed = b.closed
-		addr = b.pinAddr
-		b.mu.RUnlock()
-		// Close() which sets b.closed = true can be called before Get(), Get() must exit if balancer is closed.
-		if closed {
-			return grpc.Address{Addr: ""}, nil, grpc.ErrClientConnClosing
-		}
-		if addr != "" {
-			break
-		}
-	}
-	return grpc.Address{Addr: addr}, func() {}, nil
-}
-
-func (b *GRPC17Health) Notify() <-chan []grpc.Address { return b.notifyCh }
-
-func (b *GRPC17Health) Close() error {
-	b.mu.Lock()
-	// In case gRPC calls close twice. TODO: remove the checking
-	// when we are sure that gRPC wont call close twice.
-	if b.closed {
-		b.mu.Unlock()
-		<-b.donec
-		return nil
-	}
-	b.closed = true
-	b.stopOnce.Do(func() { close(b.stopc) })
-	b.pinAddr = ""
-
-	// In the case of following scenario:
-	//	1. upc is not closed; no pinned address
-	// 	2. client issues an RPC, calling invoke(), which calls Get(), enters for loop, blocks
-	// 	3. client.conn.Close() calls balancer.Close(); closed = true
-	// 	4. for loop in Get() never exits since ctx is the context passed in by the client and may not be canceled
-	// we must close upc so Get() exits from blocking on upc
-	select {
-	case <-b.upc:
-	default:
-		// terminate all waiting Get()s
-		close(b.upc)
-	}
-
-	b.mu.Unlock()
-	b.wg.Wait()
-
-	// wait for updateNotifyLoop to finish
-	<-b.donec
-	close(b.notifyCh)
-
-	return nil
-}
-
-func grpcHealthCheck(ep string, dialFunc func(ep string, dopts ...grpc.DialOption) (*grpc.ClientConn, error)) (bool, error) {
-	conn, err := dialFunc(ep)
-	if err != nil {
-		return false, err
-	}
-	defer conn.Close()
-	cli := healthpb.NewHealthClient(conn)
-	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
-	resp, err := cli.Check(ctx, &healthpb.HealthCheckRequest{})
-	cancel()
-	if err != nil {
-		if s, ok := status.FromError(err); ok && s.Code() == codes.Unavailable {
-			if s.Message() == unknownService { // etcd < v3.3.0
-				return true, nil
-			}
-		}
-		return false, err
-	}
-	return resp.Status == healthpb.HealthCheckResponse_SERVING, nil
-}
-
-func hasAddr(addrs []grpc.Address, targetAddr string) bool {
-	for _, addr := range addrs {
-		if targetAddr == addr.Addr {
-			return true
-		}
-	}
-	return false
-}
-
-func getHost(ep string) string {
-	url, uerr := url.Parse(ep)
-	if uerr != nil || !strings.Contains(ep, "://") {
-		return ep
-	}
-	return url.Host
-}
-
-func eps2addrs(eps []string) []grpc.Address {
-	addrs := make([]grpc.Address, len(eps))
-	for i := range eps {
-		addrs[i].Addr = getHost(eps[i])
-	}
-	return addrs
-}
-
-func getHostPort2ep(eps []string) map[string]string {
-	hm := make(map[string]string, len(eps))
-	for i := range eps {
-		_, host, _ := parseEndpoint(eps[i])
-		hm[host] = eps[i]
-	}
-	return hm
-}
-
-func parseEndpoint(endpoint string) (proto string, host string, scheme string) {
-	proto = "tcp"
-	host = endpoint
-	url, uerr := url.Parse(endpoint)
-	if uerr != nil || !strings.Contains(endpoint, "://") {
-		return proto, host, scheme
-	}
-	scheme = url.Scheme
-
-	// strip scheme:// prefix since grpc dials by host
-	host = url.Host
-	switch url.Scheme {
-	case "http", "https":
-	case "unix", "unixs":
-		proto = "unix"
-		host = url.Host + url.Path
-	default:
-		proto, host = "", ""
-	}
-	return proto, host, scheme
-}
diff --git a/vendor/go.etcd.io/etcd/clientv3/balancer/picker/err.go b/vendor/go.etcd.io/etcd/clientv3/balancer/picker/err.go
index c70ce15..9e04378 100644
--- a/vendor/go.etcd.io/etcd/clientv3/balancer/picker/err.go
+++ b/vendor/go.etcd.io/etcd/clientv3/balancer/picker/err.go
@@ -22,13 +22,18 @@
 
 // NewErr returns a picker that always returns err on "Pick".
 func NewErr(err error) Picker {
-	return &errPicker{err: err}
+	return &errPicker{p: Error, err: err}
 }
 
 type errPicker struct {
+	p   Policy
 	err error
 }
 
-func (p *errPicker) Pick(context.Context, balancer.PickOptions) (balancer.SubConn, func(balancer.DoneInfo), error) {
-	return nil, nil, p.err
+func (ep *errPicker) String() string {
+	return ep.p.String()
+}
+
+func (ep *errPicker) Pick(context.Context, balancer.PickOptions) (balancer.SubConn, func(balancer.DoneInfo), error) {
+	return nil, nil, ep.err
 }
diff --git a/vendor/go.etcd.io/etcd/clientv3/balancer/picker/picker.go b/vendor/go.etcd.io/etcd/clientv3/balancer/picker/picker.go
index 7ea761b..bd1a5d2 100644
--- a/vendor/go.etcd.io/etcd/clientv3/balancer/picker/picker.go
+++ b/vendor/go.etcd.io/etcd/clientv3/balancer/picker/picker.go
@@ -15,10 +15,77 @@
 package picker
 
 import (
+	"fmt"
+
+	"go.uber.org/zap"
 	"google.golang.org/grpc/balancer"
+	"google.golang.org/grpc/resolver"
 )
 
 // Picker defines balancer Picker methods.
 type Picker interface {
 	balancer.Picker
+	String() string
+}
+
+// Config defines picker configuration.
+type Config struct {
+	// Policy specifies etcd clientv3's built in balancer policy.
+	Policy Policy
+
+	// Logger defines picker logging object.
+	Logger *zap.Logger
+
+	// SubConnToResolverAddress maps each gRPC sub-connection to an address.
+	// Basically, it is a list of addresses that the Picker can pick from.
+	SubConnToResolverAddress map[balancer.SubConn]resolver.Address
+}
+
+// Policy defines balancer picker policy.
+type Policy uint8
+
+const (
+	// Error is error picker policy.
+	Error Policy = iota
+
+	// RoundrobinBalanced balances loads over multiple endpoints
+	// and implements failover in roundrobin fashion.
+	RoundrobinBalanced
+
+	// Custom defines custom balancer picker.
+	// TODO: custom picker is not supported yet.
+	Custom
+)
+
+func (p Policy) String() string {
+	switch p {
+	case Error:
+		return "picker-error"
+
+	case RoundrobinBalanced:
+		return "picker-roundrobin-balanced"
+
+	case Custom:
+		panic("'custom' picker policy is not supported yet")
+
+	default:
+		panic(fmt.Errorf("invalid balancer picker policy (%d)", p))
+	}
+}
+
+// New creates a new Picker.
+func New(cfg Config) Picker {
+	switch cfg.Policy {
+	case Error:
+		panic("'error' picker policy is not supported here; use 'picker.NewErr'")
+
+	case RoundrobinBalanced:
+		return newRoundrobinBalanced(cfg)
+
+	case Custom:
+		panic("'custom' picker policy is not supported yet")
+
+	default:
+		panic(fmt.Errorf("invalid balancer picker policy (%d)", cfg.Policy))
+	}
 }
diff --git a/vendor/go.etcd.io/etcd/clientv3/balancer/picker/picker_policy.go b/vendor/go.etcd.io/etcd/clientv3/balancer/picker/picker_policy.go
deleted file mode 100644
index 7bca39c..0000000
--- a/vendor/go.etcd.io/etcd/clientv3/balancer/picker/picker_policy.go
+++ /dev/null
@@ -1,49 +0,0 @@
-// Copyright 2018 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 picker
-
-import "fmt"
-
-// Policy defines balancer picker policy.
-type Policy uint8
-
-const (
-	// TODO: custom picker is not supported yet.
-	// custom defines custom balancer picker.
-	custom Policy = iota
-
-	// RoundrobinBalanced balance loads over multiple endpoints
-	// and implements failover in roundrobin fashion.
-	RoundrobinBalanced Policy = iota
-
-	// TODO: only send loads to pinned address "RoundrobinFailover"
-	// just like how 3.3 client works
-	//
-	// TODO: prioritize leader
-	// TODO: health-check
-	// TODO: weighted roundrobin
-	// TODO: power of two random choice
-)
-
-func (p Policy) String() string {
-	switch p {
-	case custom:
-		panic("'custom' picker policy is not supported yet")
-	case RoundrobinBalanced:
-		return "etcd-client-roundrobin-balanced"
-	default:
-		panic(fmt.Errorf("invalid balancer picker policy (%d)", p))
-	}
-}
diff --git a/vendor/go.etcd.io/etcd/clientv3/balancer/picker/roundrobin_balanced.go b/vendor/go.etcd.io/etcd/clientv3/balancer/picker/roundrobin_balanced.go
index b043d57..1b8b285 100644
--- a/vendor/go.etcd.io/etcd/clientv3/balancer/picker/roundrobin_balanced.go
+++ b/vendor/go.etcd.io/etcd/clientv3/balancer/picker/roundrobin_balanced.go
@@ -24,32 +24,33 @@
 	"google.golang.org/grpc/resolver"
 )
 
-// NewRoundrobinBalanced returns a new roundrobin balanced picker.
-func NewRoundrobinBalanced(
-	lg *zap.Logger,
-	scs []balancer.SubConn,
-	addrToSc map[resolver.Address]balancer.SubConn,
-	scToAddr map[balancer.SubConn]resolver.Address,
-) Picker {
+// newRoundrobinBalanced returns a new roundrobin balanced picker.
+func newRoundrobinBalanced(cfg Config) Picker {
+	scs := make([]balancer.SubConn, 0, len(cfg.SubConnToResolverAddress))
+	for sc := range cfg.SubConnToResolverAddress {
+		scs = append(scs, sc)
+	}
 	return &rrBalanced{
-		lg:       lg,
+		p:        RoundrobinBalanced,
+		lg:       cfg.Logger,
 		scs:      scs,
-		addrToSc: addrToSc,
-		scToAddr: scToAddr,
+		scToAddr: cfg.SubConnToResolverAddress,
 	}
 }
 
 type rrBalanced struct {
+	p Policy
+
 	lg *zap.Logger
 
-	mu   sync.RWMutex
-	next int
-	scs  []balancer.SubConn
-
-	addrToSc map[resolver.Address]balancer.SubConn
+	mu       sync.RWMutex
+	next     int
+	scs      []balancer.SubConn
 	scToAddr map[balancer.SubConn]resolver.Address
 }
 
+func (rb *rrBalanced) String() string { return rb.p.String() }
+
 // Pick is called for every client request.
 func (rb *rrBalanced) Pick(ctx context.Context, opts balancer.PickOptions) (balancer.SubConn, func(balancer.DoneInfo), error) {
 	rb.mu.RLock()
@@ -68,6 +69,7 @@
 
 	rb.lg.Debug(
 		"picked",
+		zap.String("picker", rb.p.String()),
 		zap.String("address", picked),
 		zap.Int("subconn-index", cur),
 		zap.Int("subconn-size", n),
@@ -77,6 +79,7 @@
 		// TODO: error handling?
 		fss := []zapcore.Field{
 			zap.Error(info.Err),
+			zap.String("picker", rb.p.String()),
 			zap.String("address", picked),
 			zap.Bool("success", info.Err == nil),
 			zap.Bool("bytes-sent", info.BytesSent),
diff --git a/vendor/go.etcd.io/etcd/clientv3/balancer/utils.go b/vendor/go.etcd.io/etcd/clientv3/balancer/utils.go
index a11faeb..48eb875 100644
--- a/vendor/go.etcd.io/etcd/clientv3/balancer/utils.go
+++ b/vendor/go.etcd.io/etcd/clientv3/balancer/utils.go
@@ -29,9 +29,9 @@
 	return fmt.Sprintf("%p", sc)
 }
 
-func scsToStrings(scs map[resolver.Address]balancer.SubConn) (ss []string) {
+func scsToStrings(scs map[balancer.SubConn]resolver.Address) (ss []string) {
 	ss = make([]string, 0, len(scs))
-	for a, sc := range scs {
+	for sc, a := range scs {
 		ss = append(ss, fmt.Sprintf("%s (%s)", a.Addr, scToString(sc)))
 	}
 	sort.Strings(ss)