diff --git a/vendor/google.golang.org/grpc/pickfirst.go b/vendor/google.golang.org/grpc/pickfirst.go
index d1e38aa..c43dac9 100644
--- a/vendor/google.golang.org/grpc/pickfirst.go
+++ b/vendor/google.golang.org/grpc/pickfirst.go
@@ -19,12 +19,14 @@
 package grpc
 
 import (
-	"context"
+	"errors"
 
 	"google.golang.org/grpc/balancer"
+	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/connectivity"
 	"google.golang.org/grpc/grpclog"
 	"google.golang.org/grpc/resolver"
+	"google.golang.org/grpc/status"
 )
 
 // PickFirstBalancerName is the name of the pick_first balancer.
@@ -45,48 +47,98 @@
 }
 
 type pickfirstBalancer struct {
-	cc balancer.ClientConn
-	sc balancer.SubConn
+	state connectivity.State
+	cc    balancer.ClientConn
+	sc    balancer.SubConn
 }
 
+var _ balancer.V2Balancer = &pickfirstBalancer{} // Assert we implement v2
+
 func (b *pickfirstBalancer) HandleResolvedAddrs(addrs []resolver.Address, err error) {
 	if err != nil {
-		grpclog.Infof("pickfirstBalancer: HandleResolvedAddrs called with error %v", err)
+		b.ResolverError(err)
 		return
 	}
-	if b.sc == nil {
-		b.sc, err = b.cc.NewSubConn(addrs, balancer.NewSubConnOptions{})
-		if err != nil {
-			//TODO(yuxuanli): why not change the cc state to Idle?
-			grpclog.Errorf("pickfirstBalancer: failed to NewSubConn: %v", err)
-			return
-		}
-		b.cc.UpdateBalancerState(connectivity.Idle, &picker{sc: b.sc})
-		b.sc.Connect()
-	} else {
-		b.sc.UpdateAddresses(addrs)
-		b.sc.Connect()
-	}
+	b.UpdateClientConnState(balancer.ClientConnState{ResolverState: resolver.State{Addresses: addrs}}) // Ignore error
 }
 
 func (b *pickfirstBalancer) HandleSubConnStateChange(sc balancer.SubConn, s connectivity.State) {
-	grpclog.Infof("pickfirstBalancer: HandleSubConnStateChange: %p, %v", sc, s)
+	b.UpdateSubConnState(sc, balancer.SubConnState{ConnectivityState: s})
+}
+
+func (b *pickfirstBalancer) ResolverError(err error) {
+	switch b.state {
+	case connectivity.TransientFailure, connectivity.Idle, connectivity.Connecting:
+		// Set a failing picker if we don't have a good picker.
+		b.cc.UpdateState(balancer.State{ConnectivityState: connectivity.TransientFailure,
+			Picker: &picker{err: status.Errorf(codes.Unavailable, "name resolver error: %v", err)}},
+		)
+	}
+	if grpclog.V(2) {
+		grpclog.Infof("pickfirstBalancer: ResolverError called with error %v", err)
+	}
+}
+
+func (b *pickfirstBalancer) UpdateClientConnState(cs balancer.ClientConnState) error {
+	if len(cs.ResolverState.Addresses) == 0 {
+		b.ResolverError(errors.New("produced zero addresses"))
+		return balancer.ErrBadResolverState
+	}
+	if b.sc == nil {
+		var err error
+		b.sc, err = b.cc.NewSubConn(cs.ResolverState.Addresses, balancer.NewSubConnOptions{})
+		if err != nil {
+			if grpclog.V(2) {
+				grpclog.Errorf("pickfirstBalancer: failed to NewSubConn: %v", err)
+			}
+			b.state = connectivity.TransientFailure
+			b.cc.UpdateState(balancer.State{ConnectivityState: connectivity.TransientFailure,
+				Picker: &picker{err: status.Errorf(codes.Unavailable, "error creating connection: %v", err)}},
+			)
+			return balancer.ErrBadResolverState
+		}
+		b.state = connectivity.Idle
+		b.cc.UpdateState(balancer.State{ConnectivityState: connectivity.Idle, Picker: &picker{result: balancer.PickResult{SubConn: b.sc}}})
+		b.sc.Connect()
+	} else {
+		b.sc.UpdateAddresses(cs.ResolverState.Addresses)
+		b.sc.Connect()
+	}
+	return nil
+}
+
+func (b *pickfirstBalancer) UpdateSubConnState(sc balancer.SubConn, s balancer.SubConnState) {
+	if grpclog.V(2) {
+		grpclog.Infof("pickfirstBalancer: HandleSubConnStateChange: %p, %v", sc, s)
+	}
 	if b.sc != sc {
-		grpclog.Infof("pickfirstBalancer: ignored state change because sc is not recognized")
+		if grpclog.V(2) {
+			grpclog.Infof("pickfirstBalancer: ignored state change because sc is not recognized")
+		}
 		return
 	}
-	if s == connectivity.Shutdown {
+	b.state = s.ConnectivityState
+	if s.ConnectivityState == connectivity.Shutdown {
 		b.sc = nil
 		return
 	}
 
-	switch s {
+	switch s.ConnectivityState {
 	case connectivity.Ready, connectivity.Idle:
-		b.cc.UpdateBalancerState(s, &picker{sc: sc})
+		b.cc.UpdateState(balancer.State{ConnectivityState: s.ConnectivityState, Picker: &picker{result: balancer.PickResult{SubConn: sc}}})
 	case connectivity.Connecting:
-		b.cc.UpdateBalancerState(s, &picker{err: balancer.ErrNoSubConnAvailable})
+		b.cc.UpdateState(balancer.State{ConnectivityState: s.ConnectivityState, Picker: &picker{err: balancer.ErrNoSubConnAvailable}})
 	case connectivity.TransientFailure:
-		b.cc.UpdateBalancerState(s, &picker{err: balancer.ErrTransientFailure})
+		err := balancer.ErrTransientFailure
+		// TODO: this can be unconditional after the V1 API is removed, as
+		// SubConnState will always contain a connection error.
+		if s.ConnectionError != nil {
+			err = balancer.TransientFailureError(s.ConnectionError)
+		}
+		b.cc.UpdateState(balancer.State{
+			ConnectivityState: s.ConnectivityState,
+			Picker:            &picker{err: err},
+		})
 	}
 }
 
@@ -94,15 +146,12 @@
 }
 
 type picker struct {
-	err error
-	sc  balancer.SubConn
+	result balancer.PickResult
+	err    error
 }
 
-func (p *picker) Pick(ctx context.Context, opts balancer.PickOptions) (balancer.SubConn, func(balancer.DoneInfo), error) {
-	if p.err != nil {
-		return nil, nil, p.err
-	}
-	return p.sc, nil, nil
+func (p *picker) Pick(info balancer.PickInfo) (balancer.PickResult, error) {
+	return p.result, p.err
 }
 
 func init() {