diff --git a/clientconn.go b/clientconn.go
index 42221882..040206a1 100644
--- a/clientconn.go
+++ b/clientconn.go
@@ -35,6 +35,7 @@ package grpc
 
 import (
 	"errors"
+	"fmt"
 	"net"
 	"strings"
 	"sync"
@@ -182,6 +183,23 @@ const (
 	Shutdown
 )
 
+func (s ConnectivityState) String() string {
+	switch s {
+	case Idle:
+		return "IDLE"
+	case Connecting:
+		return "CONNECTING"
+	case Ready:
+		return "READY"
+	case TransientFailure:
+		return "TRANSIENT_FAILURE"
+	case Shutdown:
+		return "SHUTDOWN"
+	default:
+		panic(fmt.Sprintf("unknown connectivity state: %d", s))
+	}
+}
+
 // ClientConn represents a client connection to an RPC service.
 type ClientConn struct {
 	target       string
@@ -212,27 +230,31 @@ func (cc *ClientConn) State() ConnectivityState {
 // WaitForStateChange returns true when the state changes to something other than the
 // sourceState and false if timeout fires.
 func (cc *ClientConn) WaitForStateChange(timeout time.Duration, sourceState ConnectivityState) bool {
+	start := time.Now()
 	cc.mu.Lock()
 	defer cc.mu.Unlock()
 	if sourceState != cc.state {
 		return true
 	}
-	// Shutdown state is a sink -- once it is entered, no furhter state change could happen.
-	if sourceState == Shutdown {
-		return false
-	}
 	done := make(chan struct{})
+	expired := timeout <= time.Since(start)
 	go func() {
 		select {
-		case <-time.After(timeout):
+		case <-time.After(timeout-time.Since(start)):
+			cc.mu.Lock()
+			expired = true
 			cc.stateCV.Broadcast()
+			cc.mu.Unlock()
 		case <-done:
 		}
 	}()
+	defer close(done)
 	for sourceState == cc.state {
 		cc.stateCV.Wait()
+		if expired {
+			return false
+		}
 	}
-	close(done)
 	return true
 }
 
@@ -242,6 +264,7 @@ func (cc *ClientConn) resetTransport(closeTransport bool) error {
 	for {
 		cc.mu.Lock()
 		cc.state = Connecting
+		cc.stateCV.Broadcast()
 		t := cc.transport
 		ts := cc.transportSeq
 		// Avoid wait() picking up a dying transport unnecessarily.
@@ -280,6 +303,7 @@ func (cc *ClientConn) resetTransport(closeTransport bool) error {
 		if err != nil {
 			cc.mu.Lock()
 			cc.state = TransientFailure
+			cc.stateCV.Broadcast()
 			cc.mu.Unlock()
 			sleepTime -= time.Since(connectTime)
 			if sleepTime < 0 {
@@ -304,6 +328,7 @@ func (cc *ClientConn) resetTransport(closeTransport bool) error {
 			return ErrClientConnClosing
 		}
 		cc.state = Ready
+		cc.stateCV.Broadcast()
 		cc.transport = newTransport
 		cc.transportSeq = ts + 1
 		if cc.ready != nil {
@@ -327,6 +352,7 @@ func (cc *ClientConn) transportMonitor() {
 		case <-cc.transport.Error():
 			cc.mu.Lock()
 			cc.state = TransientFailure
+			cc.stateCV.Broadcast()
 			cc.mu.Unlock()
 			if err := cc.resetTransport(true); err != nil {
 				// The ClientConn is closing.
@@ -381,6 +407,7 @@ func (cc *ClientConn) Close() error {
 		return ErrClientConnClosing
 	}
 	cc.state = Shutdown
+	cc.stateCV.Broadcast()
 	if cc.ready != nil {
 		close(cc.ready)
 		cc.ready = nil
diff --git a/credentials/credentials.go b/credentials/credentials.go
index c1a331e8..0c2b24c0 100644
--- a/credentials/credentials.go
+++ b/credentials/credentials.go
@@ -51,7 +51,7 @@ import (
 
 var (
 	// alpnProtoStr are the specified application level protocols for gRPC.
-	alpnProtoStr = []string{"h2"}
+	alpnProtoStr = []string{"h2", "h2-14", "h2-15", "h2-16"}
 )
 
 // Credentials defines the common interface all supported credentials must
diff --git a/test/end2end_test.go b/test/end2end_test.go
index 9dc667c0..6462c080 100644
--- a/test/end2end_test.go
+++ b/test/end2end_test.go
@@ -354,6 +354,15 @@ func TestTimeoutOnDeadServer(t *testing.T) {
 func testTimeoutOnDeadServer(t *testing.T, e env) {
 	s, cc := setUp(nil, math.MaxUint32, "", e)
 	tc := testpb.NewTestServiceClient(cc)
+	if ok := cc.WaitForStateChange(time.Second, grpc.Idle); !ok {
+		t.Fatalf("cc.WaitForStateChange(_, %s) = %t, want true", grpc.Idle, ok)
+	}
+	if ok := cc.WaitForStateChange(time.Second, grpc.Connecting); !ok {
+		t.Fatalf("cc.WaitForStateChange(_, %s) = %t, want true", grpc.Connecting, ok)
+	}
+	if cc.State() != grpc.Ready {
+		t.Fatalf("cc.State() = %s, want %s", cc.State(), grpc.Ready)
+	}
 	s.Stop()
 	// Set -1 as the timeout to make sure if transportMonitor gets error
 	// notification in time the failure path of the 1st invoke of
@@ -362,6 +371,13 @@ func testTimeoutOnDeadServer(t *testing.T, e env) {
 	if _, err := tc.EmptyCall(ctx, &testpb.Empty{}); grpc.Code(err) != codes.DeadlineExceeded {
 		t.Fatalf("TestService/EmptyCall(%v, _) = _, error %v, want _, error code: %d", ctx, err, codes.DeadlineExceeded)
 	}
+	if ok := cc.WaitForStateChange(time.Second, grpc.Ready); !ok {
+		t.Fatalf("cc.WaitForStateChange(_, %s) = %t, want true", grpc.Connecting, ok)
+	}
+	state := cc.State()
+	if state != grpc.Connecting && state != grpc.TransientFailure {
+		t.Fatalf("cc.State() = %s, want %s or %s", state, grpc.Connecting, grpc.TransientFailure)
+	}
 	cc.Close()
 }
 
@@ -461,8 +477,20 @@ func TestEmptyUnaryWithUserAgent(t *testing.T) {
 
 func testEmptyUnaryWithUserAgent(t *testing.T, e env) {
 	s, cc := setUp(nil, math.MaxUint32, testAppUA, e)
+	// Wait until cc is connected.
+	if ok := cc.WaitForStateChange(time.Second, grpc.Idle); !ok {
+		t.Fatalf("cc.WaitForStateChange(_, %s) = %t, want true", grpc.Idle, ok)
+	}
+	if ok := cc.WaitForStateChange(10 * time.Second, grpc.Connecting); !ok {
+		t.Fatalf("cc.WaitForStateChange(_, %s) = %t, want true", grpc.Connecting, ok)
+	}
+	if cc.State() != grpc.Ready {
+		t.Fatalf("cc.State() = %s, want %s", cc.State(), grpc.Ready)
+	}
+	if ok := cc.WaitForStateChange(time.Second, grpc.Ready); ok {
+		t.Fatalf("cc.WaitForStateChange(_, %s) = %t, want false", grpc.Ready, ok)
+	}
 	tc := testpb.NewTestServiceClient(cc)
-	defer tearDown(s, cc)
 	var header metadata.MD
 	reply, err := tc.EmptyCall(context.Background(), &testpb.Empty{}, grpc.Header(&header))
 	if err != nil || !proto.Equal(&testpb.Empty{}, reply) {
@@ -471,6 +499,13 @@ func testEmptyUnaryWithUserAgent(t *testing.T, e env) {
 	if v, ok := header["ua"]; !ok || v != testAppUA {
 		t.Fatalf("header[\"ua\"] = %q, %t, want %q, true", v, ok, testAppUA)
 	}
+	tearDown(s, cc)
+	if ok := cc.WaitForStateChange(5 * time.Second, grpc.Ready); !ok {
+		t.Fatalf("cc.WaitForStateChange(_, %s) = %t, want true", grpc.Ready, ok)
+	}
+	if cc.State() != grpc.Shutdown {
+		t.Fatalf("cc.State() = %s, want %s", cc.State(), grpc.Shutdown)
+	}
 }
 
 func TestFailedEmptyUnary(t *testing.T) {