diff --git a/connection.go b/connection.go
index aa5abf3c0ea..d9ee5fd7baa 100644
--- a/connection.go
+++ b/connection.go
@@ -1821,7 +1821,24 @@ func (s *connection) sendPackets() error {
 }
 
 func (s *connection) maybeSendAckOnlyPacket() error {
-	packet, err := s.packer.MaybePackAckPacket(s.handshakeConfirmed)
+	if !s.handshakeConfirmed {
+		packet, err := s.packer.PackCoalescedPacket(true)
+		if err != nil {
+			return err
+		}
+		if packet == nil {
+			return nil
+		}
+		s.logCoalescedPacket(packet)
+		for _, p := range packet.packets {
+			s.sentPacketHandler.SentPacket(p.ToAckHandlerPacket(time.Now(), s.retransmissionQueue))
+		}
+		s.connIDManager.SentPacket()
+		s.sendQueue.Send(packet.buffer)
+		return nil
+	}
+
+	packet, err := s.packer.PackPacket(true)
 	if err != nil {
 		return err
 	}
@@ -1882,7 +1899,7 @@ func (s *connection) sendPacket() (bool, error) {
 
 	now := time.Now()
 	if !s.handshakeConfirmed {
-		packet, err := s.packer.PackCoalescedPacket()
+		packet, err := s.packer.PackCoalescedPacket(false)
 		if err != nil || packet == nil {
 			return false, err
 		}
@@ -1906,7 +1923,7 @@ func (s *connection) sendPacket() (bool, error) {
 		s.sendPackedPacket(packet, now)
 		return true, nil
 	}
-	packet, err := s.packer.PackPacket()
+	packet, err := s.packer.PackPacket(false)
 	if err != nil || packet == nil {
 		return false, err
 	}
diff --git a/connection_test.go b/connection_test.go
index db746d3b293..9c6d0a512bf 100644
--- a/connection_test.go
+++ b/connection_test.go
@@ -602,8 +602,8 @@ var _ = Describe("Connection", func() {
 			cryptoSetup.EXPECT().Close()
 			conn.sentPacketHandler = sph
 			p := getPacket(1)
-			packer.EXPECT().PackPacket().Return(p, nil)
-			packer.EXPECT().PackPacket().Return(nil, nil).AnyTimes()
+			packer.EXPECT().PackPacket(false).Return(p, nil)
+			packer.EXPECT().PackPacket(false).Return(nil, nil).AnyTimes()
 			runConn()
 			conn.queueControlFrame(&wire.PingFrame{})
 			conn.scheduleSending()
@@ -835,7 +835,7 @@ var _ = Describe("Connection", func() {
 			}).Times(3)
 			tracer.EXPECT().ReceivedShortHeaderPacket(gomock.Any(), gomock.Any(), gomock.Any()).Do(func(hdr *logging.ShortHeader, _ protocol.ByteCount, _ []logging.Frame) {
 			}).Times(3)
-			packer.EXPECT().PackCoalescedPacket() // only expect a single call
+			packer.EXPECT().PackCoalescedPacket(false) // only expect a single call
 
 			for i := 0; i < 3; i++ {
 				conn.handlePacket(getPacket(&wire.ExtendedHeader{
@@ -874,7 +874,7 @@ var _ = Describe("Connection", func() {
 			}).Times(3)
 			tracer.EXPECT().ReceivedShortHeaderPacket(gomock.Any(), gomock.Any(), gomock.Any()).Do(func(hdr *logging.ShortHeader, _ protocol.ByteCount, _ []logging.Frame) {
 			}).Times(3)
-			packer.EXPECT().PackCoalescedPacket().Times(3) // only expect a single call
+			packer.EXPECT().PackCoalescedPacket(false).Times(3) // only expect a single call
 
 			for i := 0; i < 3; i++ {
 				conn.handlePacket(getPacket(&wire.ExtendedHeader{
@@ -1229,8 +1229,8 @@ var _ = Describe("Connection", func() {
 			conn.sentPacketHandler = sph
 			runConn()
 			p := getPacket(1)
-			packer.EXPECT().PackPacket().Return(p, nil)
-			packer.EXPECT().PackPacket().Return(nil, nil).AnyTimes()
+			packer.EXPECT().PackPacket(false).Return(p, nil)
+			packer.EXPECT().PackPacket(false).Return(nil, nil).AnyTimes()
 			sent := make(chan struct{})
 			sender.EXPECT().WouldBlock().AnyTimes()
 			sender.EXPECT().Send(gomock.Any()).Do(func(packet *packetBuffer) { close(sent) })
@@ -1242,7 +1242,7 @@ var _ = Describe("Connection", func() {
 		It("doesn't send packets if there's nothing to send", func() {
 			conn.handshakeConfirmed = true
 			runConn()
-			packer.EXPECT().PackPacket().Return(nil, nil).AnyTimes()
+			packer.EXPECT().PackPacket(false).Return(nil, nil).AnyTimes()
 			conn.receivedPacketHandler.ReceivedPacket(0x035e, protocol.ECNNon, protocol.Encryption1RTT, time.Now(), true)
 			conn.scheduleSending()
 			time.Sleep(50 * time.Millisecond) // make sure there are no calls to mconn.Write()
@@ -1254,7 +1254,7 @@ var _ = Describe("Connection", func() {
 			sph.EXPECT().GetLossDetectionTimeout().AnyTimes()
 			sph.EXPECT().SendMode().Return(ackhandler.SendAck)
 			done := make(chan struct{})
-			packer.EXPECT().MaybePackAckPacket(false).Do(func(bool) { close(done) })
+			packer.EXPECT().PackCoalescedPacket(true).Do(func(bool) { close(done) })
 			conn.sentPacketHandler = sph
 			runConn()
 			conn.scheduleSending()
@@ -1274,8 +1274,8 @@ var _ = Describe("Connection", func() {
 			fc.EXPECT().IsNewlyBlocked().Return(true, protocol.ByteCount(1337))
 			fc.EXPECT().IsNewlyBlocked()
 			p := getPacket(1)
-			packer.EXPECT().PackPacket().Return(p, nil)
-			packer.EXPECT().PackPacket().Return(nil, nil).AnyTimes()
+			packer.EXPECT().PackPacket(false).Return(p, nil)
+			packer.EXPECT().PackPacket(false).Return(nil, nil).AnyTimes()
 			conn.connFlowController = fc
 			runConn()
 			sent := make(chan struct{})
@@ -1406,8 +1406,8 @@ var _ = Describe("Connection", func() {
 			sph.EXPECT().HasPacingBudget()
 			sph.EXPECT().TimeUntilSend().Return(time.Now().Add(time.Hour))
 			sph.EXPECT().SendMode().Return(ackhandler.SendAny).Times(3)
-			packer.EXPECT().PackPacket().Return(getPacket(10), nil)
-			packer.EXPECT().PackPacket().Return(getPacket(11), nil)
+			packer.EXPECT().PackPacket(false).Return(getPacket(10), nil)
+			packer.EXPECT().PackPacket(false).Return(getPacket(11), nil)
 			sender.EXPECT().WouldBlock().AnyTimes()
 			sender.EXPECT().Send(gomock.Any()).Times(2)
 			go func() {
@@ -1423,8 +1423,8 @@ var _ = Describe("Connection", func() {
 			sph.EXPECT().SentPacket(gomock.Any())
 			sph.EXPECT().HasPacingBudget().Return(true).AnyTimes()
 			sph.EXPECT().SendMode().Return(ackhandler.SendAny).Times(2)
-			packer.EXPECT().PackPacket().Return(getPacket(10), nil)
-			packer.EXPECT().PackPacket().Return(nil, nil)
+			packer.EXPECT().PackPacket(false).Return(getPacket(10), nil)
+			packer.EXPECT().PackPacket(false).Return(nil, nil)
 			sender.EXPECT().WouldBlock().AnyTimes()
 			sender.EXPECT().Send(gomock.Any())
 			go func() {
@@ -1441,7 +1441,7 @@ var _ = Describe("Connection", func() {
 			sph.EXPECT().HasPacingBudget()
 			sph.EXPECT().TimeUntilSend().Return(time.Now().Add(time.Hour))
 			sph.EXPECT().SendMode().Return(ackhandler.SendAny)
-			packer.EXPECT().MaybePackAckPacket(gomock.Any()).Return(getPacket(10), nil)
+			packer.EXPECT().PackPacket(true).Return(getPacket(10), nil)
 			sender.EXPECT().WouldBlock().AnyTimes()
 			sender.EXPECT().Send(gomock.Any())
 			go func() {
@@ -1460,7 +1460,7 @@ var _ = Describe("Connection", func() {
 			sph.EXPECT().HasPacingBudget().Return(true)
 			sph.EXPECT().SendMode().Return(ackhandler.SendAny)
 			sph.EXPECT().SendMode().Return(ackhandler.SendAck)
-			packer.EXPECT().PackPacket().Return(getPacket(100), nil)
+			packer.EXPECT().PackPacket(false).Return(getPacket(100), nil)
 			sender.EXPECT().WouldBlock().AnyTimes()
 			sender.EXPECT().Send(gomock.Any())
 			go func() {
@@ -1477,12 +1477,12 @@ var _ = Describe("Connection", func() {
 			sph.EXPECT().SendMode().Return(ackhandler.SendAny).AnyTimes()
 			gomock.InOrder(
 				sph.EXPECT().HasPacingBudget().Return(true),
-				packer.EXPECT().PackPacket().Return(getPacket(100), nil),
+				packer.EXPECT().PackPacket(false).Return(getPacket(100), nil),
 				sph.EXPECT().SentPacket(gomock.Any()),
 				sph.EXPECT().HasPacingBudget(),
 				sph.EXPECT().TimeUntilSend().Return(time.Now().Add(pacingDelay)),
 				sph.EXPECT().HasPacingBudget().Return(true),
-				packer.EXPECT().PackPacket().Return(getPacket(101), nil),
+				packer.EXPECT().PackPacket(false).Return(getPacket(101), nil),
 				sph.EXPECT().SentPacket(gomock.Any()),
 				sph.EXPECT().HasPacingBudget(),
 				sph.EXPECT().TimeUntilSend().Return(time.Now().Add(time.Hour)),
@@ -1507,9 +1507,9 @@ var _ = Describe("Connection", func() {
 			sph.EXPECT().HasPacingBudget()
 			sph.EXPECT().TimeUntilSend().Return(time.Now().Add(time.Hour))
 			sph.EXPECT().SendMode().Return(ackhandler.SendAny).Times(4)
-			packer.EXPECT().PackPacket().Return(getPacket(1000), nil)
-			packer.EXPECT().PackPacket().Return(getPacket(1001), nil)
-			packer.EXPECT().PackPacket().Return(getPacket(1002), nil)
+			packer.EXPECT().PackPacket(false).Return(getPacket(1000), nil)
+			packer.EXPECT().PackPacket(false).Return(getPacket(1001), nil)
+			packer.EXPECT().PackPacket(false).Return(getPacket(1002), nil)
 			written := make(chan struct{}, 3)
 			sender.EXPECT().WouldBlock().AnyTimes()
 			sender.EXPECT().Send(gomock.Any()).DoAndReturn(func(p *packetBuffer) { written <- struct{}{} }).Times(3)
@@ -1539,8 +1539,8 @@ var _ = Describe("Connection", func() {
 			sph.EXPECT().SentPacket(gomock.Any())
 			sph.EXPECT().HasPacingBudget().Return(true).AnyTimes()
 			sph.EXPECT().SendMode().Return(ackhandler.SendAny).AnyTimes()
-			packer.EXPECT().PackPacket().Return(getPacket(1000), nil)
-			packer.EXPECT().PackPacket().Return(nil, nil)
+			packer.EXPECT().PackPacket(false).Return(getPacket(1000), nil)
+			packer.EXPECT().PackPacket(false).Return(nil, nil)
 			sender.EXPECT().Send(gomock.Any()).DoAndReturn(func(p *packetBuffer) { close(written) })
 			available <- struct{}{}
 			Eventually(written).Should(BeClosed())
@@ -1562,8 +1562,8 @@ var _ = Describe("Connection", func() {
 			})
 			sph.EXPECT().HasPacingBudget().Return(true).AnyTimes()
 			sph.EXPECT().SendMode().Return(ackhandler.SendAny).AnyTimes()
-			packer.EXPECT().PackPacket().Return(getPacket(1000), nil)
-			packer.EXPECT().PackPacket().Return(nil, nil)
+			packer.EXPECT().PackPacket(false).Return(getPacket(1000), nil)
+			packer.EXPECT().PackPacket(false).Return(nil, nil)
 			sender.EXPECT().Send(gomock.Any()).DoAndReturn(func(p *packetBuffer) { close(written) })
 
 			conn.scheduleSending()
@@ -1576,7 +1576,7 @@ var _ = Describe("Connection", func() {
 			sph.EXPECT().SentPacket(gomock.Any())
 			sph.EXPECT().HasPacingBudget().Return(true).AnyTimes()
 			sph.EXPECT().SendMode().Return(ackhandler.SendAny)
-			packer.EXPECT().PackPacket().Return(getPacket(1000), nil)
+			packer.EXPECT().PackPacket(false).Return(getPacket(1000), nil)
 			written := make(chan struct{}, 1)
 			sender.EXPECT().WouldBlock()
 			sender.EXPECT().WouldBlock().Return(true).Times(2)
@@ -1597,8 +1597,8 @@ var _ = Describe("Connection", func() {
 			sph.EXPECT().HasPacingBudget().Return(true).AnyTimes()
 			sph.EXPECT().SendMode().Return(ackhandler.SendAny).AnyTimes()
 			sender.EXPECT().WouldBlock().AnyTimes()
-			packer.EXPECT().PackPacket().Return(getPacket(1001), nil)
-			packer.EXPECT().PackPacket().Return(nil, nil)
+			packer.EXPECT().PackPacket(false).Return(getPacket(1001), nil)
+			packer.EXPECT().PackPacket(false).Return(nil, nil)
 			sender.EXPECT().Send(gomock.Any()).DoAndReturn(func(p *packetBuffer) { written <- struct{}{} })
 			available <- struct{}{}
 			Eventually(written).Should(Receive())
@@ -1612,7 +1612,7 @@ var _ = Describe("Connection", func() {
 			sph.EXPECT().HasPacingBudget().Return(true)
 			sph.EXPECT().SendMode().Return(ackhandler.SendAny).AnyTimes()
 			sender.EXPECT().WouldBlock().AnyTimes()
-			packer.EXPECT().PackPacket()
+			packer.EXPECT().PackPacket(false)
 			// don't EXPECT any calls to mconn.Write()
 			go func() {
 				defer GinkgoRecover()
@@ -1681,8 +1681,8 @@ var _ = Describe("Connection", func() {
 			sph.EXPECT().HasPacingBudget().Return(true).AnyTimes()
 			sph.EXPECT().SentPacket(gomock.Any())
 			conn.sentPacketHandler = sph
-			packer.EXPECT().PackPacket().Return(getPacket(1), nil)
-			packer.EXPECT().PackPacket().Return(nil, nil)
+			packer.EXPECT().PackPacket(false).Return(getPacket(1), nil)
+			packer.EXPECT().PackPacket(false).Return(nil, nil)
 
 			go func() {
 				defer GinkgoRecover()
@@ -1700,8 +1700,8 @@ var _ = Describe("Connection", func() {
 		})
 
 		It("sets the timer to the ack timer", func() {
-			packer.EXPECT().PackPacket().Return(getPacket(1234), nil)
-			packer.EXPECT().PackPacket().Return(nil, nil)
+			packer.EXPECT().PackPacket(false).Return(getPacket(1234), nil)
+			packer.EXPECT().PackPacket(false).Return(nil, nil)
 			sph := mockackhandler.NewMockSentPacketHandler(mockCtrl)
 			sph.EXPECT().GetLossDetectionTimeout().AnyTimes()
 			sph.EXPECT().SendMode().Return(ackhandler.SendAny).AnyTimes()
@@ -1735,7 +1735,7 @@ var _ = Describe("Connection", func() {
 		conn.sentPacketHandler = sph
 		buffer := getPacketBuffer()
 		buffer.Data = append(buffer.Data, []byte("foobar")...)
-		packer.EXPECT().PackCoalescedPacket().Return(&coalescedPacket{
+		packer.EXPECT().PackCoalescedPacket(false).Return(&coalescedPacket{
 			buffer: buffer,
 			packets: []*packetContents{
 				{
@@ -1760,7 +1760,7 @@ var _ = Describe("Connection", func() {
 				},
 			},
 		}, nil)
-		packer.EXPECT().PackCoalescedPacket().AnyTimes()
+		packer.EXPECT().PackCoalescedPacket(false).AnyTimes()
 
 		sph.EXPECT().GetLossDetectionTimeout().AnyTimes()
 		sph.EXPECT().SendMode().Return(ackhandler.SendAny).AnyTimes()
@@ -1811,7 +1811,7 @@ var _ = Describe("Connection", func() {
 	})
 
 	It("cancels the HandshakeComplete context when the handshake completes", func() {
-		packer.EXPECT().PackCoalescedPacket().AnyTimes()
+		packer.EXPECT().PackCoalescedPacket(false).AnyTimes()
 		finishHandshake := make(chan struct{})
 		sph := mockackhandler.NewMockSentPacketHandler(mockCtrl)
 		conn.sentPacketHandler = sph
@@ -1847,7 +1847,7 @@ var _ = Describe("Connection", func() {
 
 	It("sends a connection ticket when the handshake completes", func() {
 		const size = protocol.MaxPostHandshakeCryptoFrameSize * 3 / 2
-		packer.EXPECT().PackCoalescedPacket().AnyTimes()
+		packer.EXPECT().PackCoalescedPacket(false).AnyTimes()
 		finishHandshake := make(chan struct{})
 		connRunner.EXPECT().Retire(clientDestConnID)
 		go func() {
@@ -1891,7 +1891,7 @@ var _ = Describe("Connection", func() {
 	})
 
 	It("doesn't cancel the HandshakeComplete context when the handshake fails", func() {
-		packer.EXPECT().PackCoalescedPacket().AnyTimes()
+		packer.EXPECT().PackCoalescedPacket(false).AnyTimes()
 		streamManager.EXPECT().CloseWithError(gomock.Any())
 		expectReplaceWithClosed()
 		packer.EXPECT().PackConnectionClose(gomock.Any()).Return(&coalescedPacket{buffer: getPacketBuffer()}, nil)
@@ -1924,7 +1924,7 @@ var _ = Describe("Connection", func() {
 		conn.sentPacketHandler = sph
 		done := make(chan struct{})
 		connRunner.EXPECT().Retire(clientDestConnID)
-		packer.EXPECT().PackPacket().DoAndReturn(func() (*packedPacket, error) {
+		packer.EXPECT().PackPacket(false).DoAndReturn(func(bool) (*packedPacket, error) {
 			frames, _ := conn.framer.AppendControlFrames(nil, protocol.MaxByteCount)
 			Expect(frames).ToNot(BeEmpty())
 			Expect(frames[0].Frame).To(BeEquivalentTo(&wire.HandshakeDoneFrame{}))
@@ -1936,7 +1936,7 @@ var _ = Describe("Connection", func() {
 				buffer: getPacketBuffer(),
 			}, nil
 		})
-		packer.EXPECT().PackPacket().AnyTimes()
+		packer.EXPECT().PackPacket(false).AnyTimes()
 		go func() {
 			defer GinkgoRecover()
 			cryptoSetup.EXPECT().RunHandshake()
@@ -2014,7 +2014,7 @@ var _ = Describe("Connection", func() {
 			}
 			streamManager.EXPECT().UpdateLimits(params)
 			packer.EXPECT().HandleTransportParameters(params)
-			packer.EXPECT().PackCoalescedPacket().MaxTimes(3)
+			packer.EXPECT().PackCoalescedPacket(false).MaxTimes(3)
 			Expect(conn.earlyConnReady()).ToNot(BeClosed())
 			connRunner.EXPECT().GetStatelessResetToken(gomock.Any()).Times(2)
 			connRunner.EXPECT().Add(gomock.Any(), conn).Times(2)
@@ -2066,7 +2066,7 @@ var _ = Describe("Connection", func() {
 			setRemoteIdleTimeout(5 * time.Second)
 			conn.lastPacketReceivedTime = time.Now().Add(-5 * time.Second / 2)
 			sent := make(chan struct{})
-			packer.EXPECT().PackCoalescedPacket().Do(func() (*packedPacket, error) {
+			packer.EXPECT().PackCoalescedPacket(false).Do(func(bool) (*packedPacket, error) {
 				close(sent)
 				return nil, nil
 			})
@@ -2079,7 +2079,7 @@ var _ = Describe("Connection", func() {
 			setRemoteIdleTimeout(time.Hour)
 			conn.lastPacketReceivedTime = time.Now().Add(-protocol.MaxKeepAliveInterval).Add(-time.Millisecond)
 			sent := make(chan struct{})
-			packer.EXPECT().PackCoalescedPacket().Do(func() (*packedPacket, error) {
+			packer.EXPECT().PackCoalescedPacket(false).Do(func(bool) (*packedPacket, error) {
 				close(sent)
 				return nil, nil
 			})
@@ -2198,7 +2198,7 @@ var _ = Describe("Connection", func() {
 
 		It("closes the connection due to the idle timeout before handshake", func() {
 			conn.config.HandshakeIdleTimeout = 0
-			packer.EXPECT().PackCoalescedPacket().AnyTimes()
+			packer.EXPECT().PackCoalescedPacket(false).AnyTimes()
 			connRunner.EXPECT().Remove(gomock.Any()).AnyTimes()
 			cryptoSetup.EXPECT().Close()
 			gomock.InOrder(
@@ -2224,7 +2224,7 @@ var _ = Describe("Connection", func() {
 		})
 
 		It("closes the connection due to the idle timeout after handshake", func() {
-			packer.EXPECT().PackCoalescedPacket().AnyTimes()
+			packer.EXPECT().PackCoalescedPacket(false).AnyTimes()
 			gomock.InOrder(
 				connRunner.EXPECT().Retire(clientDestConnID),
 				connRunner.EXPECT().Remove(gomock.Any()),
@@ -2743,7 +2743,7 @@ var _ = Describe("Client Connection", func() {
 				},
 			}
 			packer.EXPECT().HandleTransportParameters(gomock.Any())
-			packer.EXPECT().PackCoalescedPacket().MaxTimes(1)
+			packer.EXPECT().PackCoalescedPacket(false).MaxTimes(1)
 			tracer.EXPECT().ReceivedTransportParameters(params)
 			conn.handleTransportParameters(params)
 			conn.handleHandshakeComplete()
diff --git a/mock_packer_test.go b/mock_packer_test.go
index 54b7e482621..1e76e1b4b42 100644
--- a/mock_packer_test.go
+++ b/mock_packer_test.go
@@ -49,21 +49,6 @@ func (mr *MockPackerMockRecorder) HandleTransportParameters(arg0 interface{}) *g
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "HandleTransportParameters", reflect.TypeOf((*MockPacker)(nil).HandleTransportParameters), arg0)
 }
 
-// MaybePackAckPacket mocks base method.
-func (m *MockPacker) MaybePackAckPacket(handshakeConfirmed bool) (*packedPacket, error) {
-	m.ctrl.T.Helper()
-	ret := m.ctrl.Call(m, "MaybePackAckPacket", handshakeConfirmed)
-	ret0, _ := ret[0].(*packedPacket)
-	ret1, _ := ret[1].(error)
-	return ret0, ret1
-}
-
-// MaybePackAckPacket indicates an expected call of MaybePackAckPacket.
-func (mr *MockPackerMockRecorder) MaybePackAckPacket(handshakeConfirmed interface{}) *gomock.Call {
-	mr.mock.ctrl.T.Helper()
-	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "MaybePackAckPacket", reflect.TypeOf((*MockPacker)(nil).MaybePackAckPacket), handshakeConfirmed)
-}
-
 // MaybePackProbePacket mocks base method.
 func (m *MockPacker) MaybePackProbePacket(arg0 protocol.EncryptionLevel) (*packedPacket, error) {
 	m.ctrl.T.Helper()
@@ -95,18 +80,18 @@ func (mr *MockPackerMockRecorder) PackApplicationClose(arg0 interface{}) *gomock
 }
 
 // PackCoalescedPacket mocks base method.
-func (m *MockPacker) PackCoalescedPacket() (*coalescedPacket, error) {
+func (m *MockPacker) PackCoalescedPacket(onlyAck bool) (*coalescedPacket, error) {
 	m.ctrl.T.Helper()
-	ret := m.ctrl.Call(m, "PackCoalescedPacket")
+	ret := m.ctrl.Call(m, "PackCoalescedPacket", onlyAck)
 	ret0, _ := ret[0].(*coalescedPacket)
 	ret1, _ := ret[1].(error)
 	return ret0, ret1
 }
 
 // PackCoalescedPacket indicates an expected call of PackCoalescedPacket.
-func (mr *MockPackerMockRecorder) PackCoalescedPacket() *gomock.Call {
+func (mr *MockPackerMockRecorder) PackCoalescedPacket(onlyAck interface{}) *gomock.Call {
 	mr.mock.ctrl.T.Helper()
-	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "PackCoalescedPacket", reflect.TypeOf((*MockPacker)(nil).PackCoalescedPacket))
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "PackCoalescedPacket", reflect.TypeOf((*MockPacker)(nil).PackCoalescedPacket), onlyAck)
 }
 
 // PackConnectionClose mocks base method.
@@ -140,18 +125,18 @@ func (mr *MockPackerMockRecorder) PackMTUProbePacket(ping, size interface{}) *go
 }
 
 // PackPacket mocks base method.
-func (m *MockPacker) PackPacket() (*packedPacket, error) {
+func (m *MockPacker) PackPacket(onlyAck bool) (*packedPacket, error) {
 	m.ctrl.T.Helper()
-	ret := m.ctrl.Call(m, "PackPacket")
+	ret := m.ctrl.Call(m, "PackPacket", onlyAck)
 	ret0, _ := ret[0].(*packedPacket)
 	ret1, _ := ret[1].(error)
 	return ret0, ret1
 }
 
 // PackPacket indicates an expected call of PackPacket.
-func (mr *MockPackerMockRecorder) PackPacket() *gomock.Call {
+func (mr *MockPackerMockRecorder) PackPacket(onlyAck interface{}) *gomock.Call {
 	mr.mock.ctrl.T.Helper()
-	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "PackPacket", reflect.TypeOf((*MockPacker)(nil).PackPacket))
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "PackPacket", reflect.TypeOf((*MockPacker)(nil).PackPacket), onlyAck)
 }
 
 // SetMaxPacketSize mocks base method.
diff --git a/packet_packer.go b/packet_packer.go
index 8e4aa73552d..8b1d4772351 100644
--- a/packet_packer.go
+++ b/packet_packer.go
@@ -16,10 +16,9 @@ import (
 )
 
 type packer interface {
-	PackCoalescedPacket() (*coalescedPacket, error)
-	PackPacket() (*packedPacket, error)
+	PackCoalescedPacket(onlyAck bool) (*coalescedPacket, error)
+	PackPacket(onlyAck bool) (*packedPacket, error)
 	MaybePackProbePacket(protocol.EncryptionLevel) (*packedPacket, error)
-	MaybePackAckPacket(handshakeConfirmed bool) (*packedPacket, error)
 	PackConnectionClose(*qerr.TransportError) (*coalescedPacket, error)
 	PackApplicationClose(*qerr.ApplicationError) (*coalescedPacket, error)
 
@@ -320,39 +319,6 @@ func (p *packetPacker) packetLength(hdr *wire.ExtendedHeader, payload *payload)
 	return hdr.GetLength(p.version) + payload.length + paddingLen
 }
 
-func (p *packetPacker) MaybePackAckPacket(handshakeConfirmed bool) (*packedPacket, error) {
-	var encLevel protocol.EncryptionLevel
-	var ack *wire.AckFrame
-	if !handshakeConfirmed {
-		ack = p.acks.GetAckFrame(protocol.EncryptionInitial, true)
-		if ack != nil {
-			encLevel = protocol.EncryptionInitial
-		} else {
-			ack = p.acks.GetAckFrame(protocol.EncryptionHandshake, true)
-			if ack != nil {
-				encLevel = protocol.EncryptionHandshake
-			}
-		}
-	}
-	if ack == nil {
-		ack = p.acks.GetAckFrame(protocol.Encryption1RTT, true)
-		if ack == nil {
-			return nil, nil
-		}
-		encLevel = protocol.Encryption1RTT
-	}
-	payload := &payload{
-		ack:    ack,
-		length: ack.Length(p.version),
-	}
-
-	sealer, hdr, err := p.getSealerAndHeader(encLevel)
-	if err != nil {
-		return nil, err
-	}
-	return p.writeSinglePacket(hdr, payload, encLevel, sealer)
-}
-
 // size is the expected size of the packet, if no padding was applied.
 func (p *packetPacker) initialPaddingLen(frames []ackhandler.Frame, size protocol.ByteCount) protocol.ByteCount {
 	// For the server, only ack-eliciting Initial packets need to be padded.
@@ -368,7 +334,7 @@ func (p *packetPacker) initialPaddingLen(frames []ackhandler.Frame, size protoco
 // PackCoalescedPacket packs a new packet.
 // It packs an Initial / Handshake if there is data to send in these packet number spaces.
 // It should only be called before the handshake is confirmed.
-func (p *packetPacker) PackCoalescedPacket() (*coalescedPacket, error) {
+func (p *packetPacker) PackCoalescedPacket(onlyAck bool) (*coalescedPacket, error) {
 	maxPacketSize := p.maxPacketSize
 	if p.perspective == protocol.PerspectiveClient {
 		maxPacketSize = protocol.MinInitialPacketSize
@@ -383,7 +349,7 @@ func (p *packetPacker) PackCoalescedPacket() (*coalescedPacket, error) {
 	}
 	var size protocol.ByteCount
 	if initialSealer != nil {
-		initialHdr, initialPayload = p.maybeGetCryptoPacket(maxPacketSize-protocol.ByteCount(initialSealer.Overhead()), size, protocol.EncryptionInitial)
+		initialHdr, initialPayload = p.maybeGetCryptoPacket(maxPacketSize-protocol.ByteCount(initialSealer.Overhead()), protocol.EncryptionInitial, onlyAck, true)
 		if initialPayload != nil {
 			size += p.packetLength(initialHdr, initialPayload) + protocol.ByteCount(initialSealer.Overhead())
 			numPackets++
@@ -392,14 +358,14 @@ func (p *packetPacker) PackCoalescedPacket() (*coalescedPacket, error) {
 
 	// Add a Handshake packet.
 	var handshakeSealer sealer
-	if size < maxPacketSize-protocol.MinCoalescedPacketSize {
+	if (onlyAck && size == 0) || (!onlyAck && size < maxPacketSize-protocol.MinCoalescedPacketSize) {
 		var err error
 		handshakeSealer, err = p.cryptoSetup.GetHandshakeSealer()
 		if err != nil && err != handshake.ErrKeysDropped && err != handshake.ErrKeysNotYetAvailable {
 			return nil, err
 		}
 		if handshakeSealer != nil {
-			handshakeHdr, handshakePayload = p.maybeGetCryptoPacket(maxPacketSize-size-protocol.ByteCount(handshakeSealer.Overhead()), size, protocol.EncryptionHandshake)
+			handshakeHdr, handshakePayload = p.maybeGetCryptoPacket(maxPacketSize-size-protocol.ByteCount(handshakeSealer.Overhead()), protocol.EncryptionHandshake, onlyAck, size == 0)
 			if handshakePayload != nil {
 				s := p.packetLength(handshakeHdr, handshakePayload) + protocol.ByteCount(handshakeSealer.Overhead())
 				size += s
@@ -411,7 +377,7 @@ func (p *packetPacker) PackCoalescedPacket() (*coalescedPacket, error) {
 	// Add a 0-RTT / 1-RTT packet.
 	var appDataSealer sealer
 	appDataEncLevel := protocol.Encryption1RTT
-	if size < maxPacketSize-protocol.MinCoalescedPacketSize {
+	if (onlyAck && size == 0) || (!onlyAck && size < maxPacketSize-protocol.MinCoalescedPacketSize) {
 		var sErr error
 		var oneRTTSealer handshake.ShortHeaderSealer
 		oneRTTSealer, sErr = p.cryptoSetup.Get1RTTSealer()
@@ -426,7 +392,7 @@ func (p *packetPacker) PackCoalescedPacket() (*coalescedPacket, error) {
 			case protocol.Encryption0RTT:
 				appDataHdr, appDataPayload = p.maybeGetAppDataPacketFor0RTT(appDataSealer, maxPacketSize-size)
 			case protocol.Encryption1RTT:
-				appDataHdr, appDataPayload = p.maybeGetShortHeaderPacket(oneRTTSealer, maxPacketSize-size, size)
+				appDataHdr, appDataPayload = p.maybeGetShortHeaderPacket(oneRTTSealer, maxPacketSize-size, onlyAck, size == 0)
 			}
 			if appDataHdr != nil && appDataPayload != nil {
 				size += p.packetLength(appDataHdr, appDataPayload) + protocol.ByteCount(appDataSealer.Overhead())
@@ -471,12 +437,12 @@ func (p *packetPacker) PackCoalescedPacket() (*coalescedPacket, error) {
 
 // PackPacket packs a packet in the application data packet number space.
 // It should be called after the handshake is confirmed.
-func (p *packetPacker) PackPacket() (*packedPacket, error) {
+func (p *packetPacker) PackPacket(onlyAck bool) (*packedPacket, error) {
 	sealer, err := p.cryptoSetup.Get1RTTSealer()
 	if err != nil {
 		return nil, err
 	}
-	hdr, payload := p.maybeGetShortHeaderPacket(sealer, p.maxPacketSize, 0)
+	hdr, payload := p.maybeGetShortHeaderPacket(sealer, p.maxPacketSize, onlyAck, true)
 	if payload == nil {
 		return nil, nil
 	}
@@ -491,7 +457,17 @@ func (p *packetPacker) PackPacket() (*packedPacket, error) {
 	}, nil
 }
 
-func (p *packetPacker) maybeGetCryptoPacket(maxPacketSize, currentSize protocol.ByteCount, encLevel protocol.EncryptionLevel) (*wire.ExtendedHeader, *payload) {
+func (p *packetPacker) maybeGetCryptoPacket(maxPacketSize protocol.ByteCount, encLevel protocol.EncryptionLevel, onlyAck, ackAllowed bool) (*wire.ExtendedHeader, *payload) {
+	if onlyAck {
+		if ack := p.acks.GetAckFrame(encLevel, true); ack != nil {
+			var payload payload
+			payload.ack = ack
+			payload.length = ack.Length(p.version)
+			return p.getLongHeader(encLevel), &payload
+		}
+		return nil, nil
+	}
+
 	var s cryptoStream
 	var hasRetransmission bool
 	//nolint:exhaustive // Initial and Handshake are the only two encryption levels here.
@@ -506,7 +482,7 @@ func (p *packetPacker) maybeGetCryptoPacket(maxPacketSize, currentSize protocol.
 
 	hasData := s.HasData()
 	var ack *wire.AckFrame
-	if encLevel == protocol.EncryptionInitial || currentSize == 0 {
+	if ackAllowed {
 		ack = p.acks.GetAckFrame(encLevel, !hasRetransmission && !hasData)
 	}
 	if !hasData && !hasRetransmission && ack == nil {
@@ -555,19 +531,19 @@ func (p *packetPacker) maybeGetAppDataPacketFor0RTT(sealer sealer, maxPacketSize
 
 	hdr := p.getLongHeader(protocol.Encryption0RTT)
 	maxPayloadSize := maxPacketSize - hdr.GetLength(p.version) - protocol.ByteCount(sealer.Overhead())
-	payload := p.maybeGetAppDataPacket(maxPayloadSize, false)
+	payload := p.maybeGetAppDataPacket(maxPayloadSize, false, false)
 	return hdr, payload
 }
 
-func (p *packetPacker) maybeGetShortHeaderPacket(sealer handshake.ShortHeaderSealer, maxPacketSize, currentSize protocol.ByteCount) (*wire.ExtendedHeader, *payload) {
+func (p *packetPacker) maybeGetShortHeaderPacket(sealer handshake.ShortHeaderSealer, maxPacketSize protocol.ByteCount, onlyAck, ackAllowed bool) (*wire.ExtendedHeader, *payload) {
 	hdr := p.getShortHeader(sealer.KeyPhase())
 	maxPayloadSize := maxPacketSize - hdr.GetLength(p.version) - protocol.ByteCount(sealer.Overhead())
-	payload := p.maybeGetAppDataPacket(maxPayloadSize, currentSize == 0)
+	payload := p.maybeGetAppDataPacket(maxPayloadSize, onlyAck, ackAllowed)
 	return hdr, payload
 }
 
-func (p *packetPacker) maybeGetAppDataPacket(maxPayloadSize protocol.ByteCount, ackAllowed bool) *payload {
-	payload := p.composeNextPacket(maxPayloadSize, ackAllowed)
+func (p *packetPacker) maybeGetAppDataPacket(maxPayloadSize protocol.ByteCount, onlyAck, ackAllowed bool) *payload {
+	payload := p.composeNextPacket(maxPayloadSize, onlyAck, ackAllowed)
 
 	// check if we have anything to send
 	if len(payload.frames) == 0 {
@@ -590,7 +566,17 @@ func (p *packetPacker) maybeGetAppDataPacket(maxPayloadSize protocol.ByteCount,
 	return payload
 }
 
-func (p *packetPacker) composeNextPacket(maxFrameSize protocol.ByteCount, ackAllowed bool) *payload {
+func (p *packetPacker) composeNextPacket(maxFrameSize protocol.ByteCount, onlyAck, ackAllowed bool) *payload {
+	if onlyAck {
+		if ack := p.acks.GetAckFrame(protocol.Encryption1RTT, true); ack != nil {
+			payload := &payload{}
+			payload.ack = ack
+			payload.length += ack.Length(p.version)
+			return payload
+		}
+		return &payload{}
+	}
+
 	payload := &payload{frames: make([]ackhandler.Frame, 0, 1)}
 
 	hasData := p.framer.HasData()
@@ -663,14 +649,14 @@ func (p *packetPacker) MaybePackProbePacket(encLevel protocol.EncryptionLevel) (
 		if err != nil {
 			return nil, err
 		}
-		hdr, payload = p.maybeGetCryptoPacket(p.maxPacketSize-protocol.ByteCount(sealer.Overhead()), 0, protocol.EncryptionInitial)
+		hdr, payload = p.maybeGetCryptoPacket(p.maxPacketSize-protocol.ByteCount(sealer.Overhead()), protocol.EncryptionInitial, false, true)
 	case protocol.EncryptionHandshake:
 		var err error
 		sealer, err = p.cryptoSetup.GetHandshakeSealer()
 		if err != nil {
 			return nil, err
 		}
-		hdr, payload = p.maybeGetCryptoPacket(p.maxPacketSize-protocol.ByteCount(sealer.Overhead()), 0, protocol.EncryptionHandshake)
+		hdr, payload = p.maybeGetCryptoPacket(p.maxPacketSize-protocol.ByteCount(sealer.Overhead()), protocol.EncryptionHandshake, false, true)
 	case protocol.Encryption1RTT:
 		oneRTTSealer, err := p.cryptoSetup.Get1RTTSealer()
 		if err != nil {
@@ -678,7 +664,7 @@ func (p *packetPacker) MaybePackProbePacket(encLevel protocol.EncryptionLevel) (
 		}
 		sealer = oneRTTSealer
 		hdr = p.getShortHeader(oneRTTSealer.KeyPhase())
-		payload = p.maybeGetAppDataPacket(p.maxPacketSize-protocol.ByteCount(sealer.Overhead())-hdr.GetLength(p.version), true)
+		payload = p.maybeGetAppDataPacket(p.maxPacketSize-protocol.ByteCount(sealer.Overhead())-hdr.GetLength(p.version), false, true)
 	default:
 		panic("unknown encryption level")
 	}
@@ -724,41 +710,6 @@ func (p *packetPacker) PackMTUProbePacket(ping ackhandler.Frame, size protocol.B
 	}, nil
 }
 
-func (p *packetPacker) getSealerAndHeader(encLevel protocol.EncryptionLevel) (sealer, *wire.ExtendedHeader, error) {
-	switch encLevel {
-	case protocol.EncryptionInitial:
-		sealer, err := p.cryptoSetup.GetInitialSealer()
-		if err != nil {
-			return nil, nil, err
-		}
-		hdr := p.getLongHeader(protocol.EncryptionInitial)
-		return sealer, hdr, nil
-	case protocol.Encryption0RTT:
-		sealer, err := p.cryptoSetup.Get0RTTSealer()
-		if err != nil {
-			return nil, nil, err
-		}
-		hdr := p.getLongHeader(protocol.Encryption0RTT)
-		return sealer, hdr, nil
-	case protocol.EncryptionHandshake:
-		sealer, err := p.cryptoSetup.GetHandshakeSealer()
-		if err != nil {
-			return nil, nil, err
-		}
-		hdr := p.getLongHeader(protocol.EncryptionHandshake)
-		return sealer, hdr, nil
-	case protocol.Encryption1RTT:
-		sealer, err := p.cryptoSetup.Get1RTTSealer()
-		if err != nil {
-			return nil, nil, err
-		}
-		hdr := p.getShortHeader(sealer.KeyPhase())
-		return sealer, hdr, nil
-	default:
-		return nil, nil, fmt.Errorf("unexpected encryption level: %s", encLevel)
-	}
-}
-
 func (p *packetPacker) getShortHeader(kp protocol.KeyPhaseBit) *wire.ExtendedHeader {
 	pn, pnLen := p.pnManager.PeekPacketNumber(protocol.Encryption1RTT)
 	hdr := &wire.ExtendedHeader{}
@@ -793,28 +744,6 @@ func (p *packetPacker) getLongHeader(encLevel protocol.EncryptionLevel) *wire.Ex
 	return hdr
 }
 
-// writeSinglePacket packs a single packet.
-func (p *packetPacker) writeSinglePacket(
-	hdr *wire.ExtendedHeader,
-	payload *payload,
-	encLevel protocol.EncryptionLevel,
-	sealer sealer,
-) (*packedPacket, error) {
-	buffer := getPacketBuffer()
-	var paddingLen protocol.ByteCount
-	if encLevel == protocol.EncryptionInitial {
-		paddingLen = p.initialPaddingLen(payload.frames, hdr.GetLength(p.version)+payload.length+protocol.ByteCount(sealer.Overhead()))
-	}
-	contents, err := p.appendPacket(buffer, hdr, payload, paddingLen, encLevel, sealer, false)
-	if err != nil {
-		return nil, err
-	}
-	return &packedPacket{
-		buffer:         buffer,
-		packetContents: contents,
-	}, nil
-}
-
 func (p *packetPacker) appendPacket(buffer *packetBuffer, header *wire.ExtendedHeader, payload *payload, padding protocol.ByteCount, encLevel protocol.EncryptionLevel, sealer sealer, isMTUProbePacket bool) (*packetContents, error) {
 	var paddingLen protocol.ByteCount
 	pnLen := protocol.ByteCount(header.PacketNumberLen)
diff --git a/packet_packer_test.go b/packet_packer_test.go
index 3d5d456b8f9..e1e9cb95125 100644
--- a/packet_packer_test.go
+++ b/packet_packer_test.go
@@ -191,7 +191,7 @@ var _ = Describe("Packet packer", func() {
 			expectAppendControlFrames()
 			f := &wire.StreamFrame{Data: []byte{0xde, 0xca, 0xfb, 0xad}}
 			expectAppendStreamFrames(ackhandler.Frame{Frame: f})
-			p, err := packer.PackCoalescedPacket()
+			p, err := packer.PackCoalescedPacket(false)
 			Expect(err).ToNot(HaveOccurred())
 			Expect(p).ToNot(BeNil())
 			Expect(p.packets).To(HaveLen(1))
@@ -220,10 +220,14 @@ var _ = Describe("Packet packer", func() {
 
 		Context("packing ACK packets", func() {
 			It("doesn't pack a packet if there's no ACK to send", func() {
+				sealingManager.EXPECT().GetInitialSealer().Return(getSealer(), nil)
+				sealingManager.EXPECT().GetHandshakeSealer().Return(getSealer(), nil)
+				sealingManager.EXPECT().Get1RTTSealer().Return(getSealer(), nil)
+				pnManager.EXPECT().PeekPacketNumber(protocol.Encryption1RTT).Return(protocol.PacketNumber(0x42), protocol.PacketNumberLen2)
 				ackFramer.EXPECT().GetAckFrame(protocol.EncryptionInitial, true)
 				ackFramer.EXPECT().GetAckFrame(protocol.EncryptionHandshake, true)
 				ackFramer.EXPECT().GetAckFrame(protocol.Encryption1RTT, true)
-				p, err := packer.MaybePackAckPacket(false)
+				p, err := packer.PackCoalescedPacket(true)
 				Expect(err).ToNot(HaveOccurred())
 				Expect(p).To(BeNil())
 			})
@@ -235,11 +239,13 @@ var _ = Describe("Packet packer", func() {
 				sealingManager.EXPECT().GetInitialSealer().Return(getSealer(), nil)
 				ack := &wire.AckFrame{AckRanges: []wire.AckRange{{Smallest: 1, Largest: 10}}}
 				ackFramer.EXPECT().GetAckFrame(protocol.EncryptionInitial, true).Return(ack)
-				p, err := packer.MaybePackAckPacket(false)
+				p, err := packer.PackCoalescedPacket(true)
 				Expect(err).NotTo(HaveOccurred())
 				Expect(p).ToNot(BeNil())
-				Expect(p.EncryptionLevel()).To(Equal(protocol.EncryptionInitial))
-				Expect(p.ack).To(Equal(ack))
+				Expect(p.packets).To(HaveLen(1))
+				Expect(p.packets[0].EncryptionLevel()).To(Equal(protocol.EncryptionInitial))
+				Expect(p.packets[0].ack).To(Equal(ack))
+				Expect(p.packets[0].frames).To(BeEmpty())
 				Expect(p.buffer.Len()).To(BeEquivalentTo(packer.maxPacketSize))
 				parsePacket(p.buffer.Data)
 			})
@@ -250,25 +256,47 @@ var _ = Describe("Packet packer", func() {
 				sealingManager.EXPECT().GetInitialSealer().Return(getSealer(), nil)
 				ack := &wire.AckFrame{AckRanges: []wire.AckRange{{Smallest: 1, Largest: 10}}}
 				ackFramer.EXPECT().GetAckFrame(protocol.EncryptionInitial, true).Return(ack)
-				p, err := packer.MaybePackAckPacket(false)
+				p, err := packer.PackCoalescedPacket(true)
 				Expect(err).NotTo(HaveOccurred())
 				Expect(p).ToNot(BeNil())
-				Expect(p.EncryptionLevel()).To(Equal(protocol.EncryptionInitial))
-				Expect(p.ack).To(Equal(ack))
+				Expect(p.packets).To(HaveLen(1))
+				Expect(p.packets[0].EncryptionLevel()).To(Equal(protocol.EncryptionInitial))
+				Expect(p.packets[0].ack).To(Equal(ack))
+				Expect(p.packets[0].frames).To(BeEmpty())
+				Expect(p.buffer.Len()).To(BeNumerically("<", 100))
+				parsePacket(p.buffer.Data)
+			})
+
+			It("packs 1-RTT ACK-only packets, before handshake confirmation", func() {
+				sealingManager.EXPECT().GetInitialSealer().Return(nil, handshake.ErrKeysDropped)
+				sealingManager.EXPECT().GetHandshakeSealer().Return(getSealer(), nil)
+				pnManager.EXPECT().PeekPacketNumber(protocol.Encryption1RTT).Return(protocol.PacketNumber(0x42), protocol.PacketNumberLen2)
+				pnManager.EXPECT().PopPacketNumber(protocol.Encryption1RTT).Return(protocol.PacketNumber(0x42))
+				sealingManager.EXPECT().Get1RTTSealer().Return(getSealer(), nil)
+				ack := &wire.AckFrame{AckRanges: []wire.AckRange{{Smallest: 1, Largest: 10}}}
+				ackFramer.EXPECT().GetAckFrame(protocol.EncryptionHandshake, true)
+				ackFramer.EXPECT().GetAckFrame(protocol.Encryption1RTT, true).Return(ack)
+				p, err := packer.PackCoalescedPacket(true)
+				Expect(err).NotTo(HaveOccurred())
+				Expect(p).ToNot(BeNil())
+				Expect(p.packets).To(HaveLen(1))
+				Expect(p.packets[0].EncryptionLevel()).To(Equal(protocol.Encryption1RTT))
+				Expect(p.packets[0].ack).To(Equal(ack))
+				Expect(p.packets[0].frames).To(BeEmpty())
 				parsePacket(p.buffer.Data)
 			})
 
-			It("packs 1-RTT ACK-only packets", func() {
+			It("packs 1-RTT ACK-only packets, after handshake confirmation", func() {
 				pnManager.EXPECT().PeekPacketNumber(protocol.Encryption1RTT).Return(protocol.PacketNumber(0x42), protocol.PacketNumberLen2)
 				pnManager.EXPECT().PopPacketNumber(protocol.Encryption1RTT).Return(protocol.PacketNumber(0x42))
 				sealingManager.EXPECT().Get1RTTSealer().Return(getSealer(), nil)
 				ack := &wire.AckFrame{AckRanges: []wire.AckRange{{Smallest: 1, Largest: 10}}}
 				ackFramer.EXPECT().GetAckFrame(protocol.Encryption1RTT, true).Return(ack)
-				p, err := packer.MaybePackAckPacket(true)
+				p, err := packer.PackPacket(true)
 				Expect(err).NotTo(HaveOccurred())
 				Expect(p).ToNot(BeNil())
-				Expect(p.EncryptionLevel()).To(Equal(protocol.Encryption1RTT))
 				Expect(p.ack).To(Equal(ack))
+				Expect(p.frames).To(BeEmpty())
 				parsePacket(p.buffer.Data)
 			})
 		})
@@ -300,7 +328,7 @@ var _ = Describe("Packet packer", func() {
 				framer.EXPECT().AppendStreamFrames(gomock.Any(), gomock.Any()).DoAndReturn(func(frames []ackhandler.Frame, _ protocol.ByteCount) ([]ackhandler.Frame, protocol.ByteCount) {
 					return frames, 0
 				})
-				p, err := packer.PackCoalescedPacket()
+				p, err := packer.PackCoalescedPacket(false)
 				Expect(p).ToNot(BeNil())
 				Expect(err).ToNot(HaveOccurred())
 				Expect(p.packets).To(HaveLen(1))
@@ -479,7 +507,7 @@ var _ = Describe("Packet packer", func() {
 				sealingManager.EXPECT().Get1RTTSealer().Return(getSealer(), nil)
 				ackFramer.EXPECT().GetAckFrame(protocol.Encryption1RTT, true)
 				framer.EXPECT().HasData()
-				p, err := packer.PackPacket()
+				p, err := packer.PackPacket(false)
 				Expect(p).To(BeNil())
 				Expect(err).ToNot(HaveOccurred())
 			})
@@ -496,7 +524,7 @@ var _ = Describe("Packet packer", func() {
 					Data:     []byte{0xde, 0xca, 0xfb, 0xad},
 				}
 				expectAppendStreamFrames(ackhandler.Frame{Frame: f})
-				p, err := packer.PackPacket()
+				p, err := packer.PackPacket(false)
 				Expect(err).ToNot(HaveOccurred())
 				Expect(p).ToNot(BeNil())
 				b, err := f.Append(nil, packer.version)
@@ -516,7 +544,7 @@ var _ = Describe("Packet packer", func() {
 					StreamID: 5,
 					Data:     []byte("foobar"),
 				}})
-				p, err := packer.PackPacket()
+				p, err := packer.PackPacket(false)
 				Expect(err).ToNot(HaveOccurred())
 				Expect(p.EncryptionLevel()).To(Equal(protocol.Encryption1RTT))
 			})
@@ -528,7 +556,7 @@ var _ = Describe("Packet packer", func() {
 				framer.EXPECT().HasData()
 				ackFramer.EXPECT().GetAckFrame(protocol.Encryption1RTT, true).Return(ack)
 				sealingManager.EXPECT().Get1RTTSealer().Return(getSealer(), nil)
-				p, err := packer.PackPacket()
+				p, err := packer.PackPacket(false)
 				Expect(err).NotTo(HaveOccurred())
 				Expect(p).ToNot(BeNil())
 				Expect(p.ack).To(Equal(ack))
@@ -546,7 +574,7 @@ var _ = Describe("Packet packer", func() {
 				}
 				expectAppendControlFrames(frames...)
 				expectAppendStreamFrames()
-				p, err := packer.PackPacket()
+				p, err := packer.PackPacket(false)
 				Expect(p).ToNot(BeNil())
 				Expect(err).ToNot(HaveOccurred())
 				Expect(p.frames).To(Equal(frames))
@@ -572,7 +600,7 @@ var _ = Describe("Packet packer", func() {
 				time.Sleep(scaleDuration(20 * time.Millisecond))
 
 				framer.EXPECT().HasData()
-				p, err := packer.PackPacket()
+				p, err := packer.PackPacket(false)
 				Expect(p).ToNot(BeNil())
 				Expect(err).ToNot(HaveOccurred())
 				Expect(p.frames).To(HaveLen(1))
@@ -600,7 +628,7 @@ var _ = Describe("Packet packer", func() {
 				time.Sleep(scaleDuration(20 * time.Millisecond))
 
 				framer.EXPECT().HasData()
-				p, err := packer.PackPacket()
+				p, err := packer.PackPacket(false)
 				Expect(p).ToNot(BeNil())
 				Expect(err).ToNot(HaveOccurred())
 				Expect(p.ack).ToNot(BeNil())
@@ -627,7 +655,7 @@ var _ = Describe("Packet packer", func() {
 						return fs, 0
 					}),
 				)
-				_, err := packer.PackPacket()
+				_, err := packer.PackPacket(false)
 				Expect(err).ToNot(HaveOccurred())
 			})
 
@@ -641,7 +669,7 @@ var _ = Describe("Packet packer", func() {
 				packer.retransmissionQueue.AddHandshake(&wire.PingFrame{})
 				handshakeStream.EXPECT().HasData()
 				ackFramer.EXPECT().GetAckFrame(protocol.EncryptionHandshake, false)
-				packet, err := packer.PackCoalescedPacket()
+				packet, err := packer.PackCoalescedPacket(false)
 				Expect(err).ToNot(HaveOccurred())
 				Expect(packet).ToNot(BeNil())
 				Expect(packet.packets).To(HaveLen(1))
@@ -684,7 +712,7 @@ var _ = Describe("Packet packer", func() {
 				ackFramer.EXPECT().GetAckFrame(protocol.Encryption1RTT, false)
 				expectAppendControlFrames()
 				expectAppendStreamFrames(ackhandler.Frame{Frame: f})
-				packet, err := packer.PackPacket()
+				packet, err := packer.PackPacket(false)
 				Expect(err).ToNot(HaveOccurred())
 				// cut off the tag that the mock sealer added
 				packet.buffer.Data = packet.buffer.Data[:packet.buffer.Len()-protocol.ByteCount(sealer.Overhead())]
@@ -735,7 +763,7 @@ var _ = Describe("Packet packer", func() {
 				ackFramer.EXPECT().GetAckFrame(protocol.Encryption1RTT, false)
 				expectAppendControlFrames()
 				expectAppendStreamFrames(ackhandler.Frame{Frame: f1}, ackhandler.Frame{Frame: f2}, ackhandler.Frame{Frame: f3})
-				p, err := packer.PackPacket()
+				p, err := packer.PackPacket(false)
 				Expect(p).ToNot(BeNil())
 				Expect(err).ToNot(HaveOccurred())
 				Expect(p.frames).To(HaveLen(3))
@@ -754,7 +782,7 @@ var _ = Describe("Packet packer", func() {
 						ackFramer.EXPECT().GetAckFrame(protocol.Encryption1RTT, false).Return(&wire.AckFrame{AckRanges: []wire.AckRange{{Smallest: 1, Largest: 1}}})
 						expectAppendControlFrames()
 						expectAppendStreamFrames()
-						p, err := packer.PackPacket()
+						p, err := packer.PackPacket(false)
 						Expect(p).ToNot(BeNil())
 						Expect(err).ToNot(HaveOccurred())
 						Expect(p.ack).ToNot(BeNil())
@@ -771,7 +799,7 @@ var _ = Describe("Packet packer", func() {
 					ackFramer.EXPECT().GetAckFrame(protocol.Encryption1RTT, false).Return(&wire.AckFrame{AckRanges: []wire.AckRange{{Smallest: 1, Largest: 1}}})
 					expectAppendControlFrames()
 					expectAppendStreamFrames()
-					p, err := packer.PackPacket()
+					p, err := packer.PackPacket(false)
 					Expect(p).ToNot(BeNil())
 					Expect(err).ToNot(HaveOccurred())
 					var hasPing bool
@@ -790,7 +818,7 @@ var _ = Describe("Packet packer", func() {
 					ackFramer.EXPECT().GetAckFrame(protocol.Encryption1RTT, false).Return(&wire.AckFrame{AckRanges: []wire.AckRange{{Smallest: 1, Largest: 1}}})
 					expectAppendControlFrames()
 					expectAppendStreamFrames()
-					p, err = packer.PackPacket()
+					p, err = packer.PackPacket(false)
 					Expect(p).ToNot(BeNil())
 					Expect(err).ToNot(HaveOccurred())
 					Expect(p.ack).ToNot(BeNil())
@@ -806,7 +834,7 @@ var _ = Describe("Packet packer", func() {
 					expectAppendControlFrames()
 					expectAppendStreamFrames()
 					ackFramer.EXPECT().GetAckFrame(protocol.Encryption1RTT, false)
-					p, err := packer.PackPacket()
+					p, err := packer.PackPacket(false)
 					Expect(err).ToNot(HaveOccurred())
 					Expect(p).To(BeNil())
 					// now add some frame to send
@@ -818,7 +846,7 @@ var _ = Describe("Packet packer", func() {
 					framer.EXPECT().HasData().Return(true)
 					ack := &wire.AckFrame{AckRanges: []wire.AckRange{{Smallest: 1, Largest: 1}}}
 					ackFramer.EXPECT().GetAckFrame(protocol.Encryption1RTT, false).Return(ack)
-					p, err = packer.PackPacket()
+					p, err = packer.PackPacket(false)
 					Expect(err).ToNot(HaveOccurred())
 					Expect(p.ack).To(Equal(ack))
 					var hasPing bool
@@ -840,7 +868,7 @@ var _ = Describe("Packet packer", func() {
 					ackFramer.EXPECT().GetAckFrame(protocol.Encryption1RTT, false)
 					expectAppendStreamFrames()
 					expectAppendControlFrames(ackhandler.Frame{Frame: &wire.MaxDataFrame{}})
-					p, err := packer.PackPacket()
+					p, err := packer.PackPacket(false)
 					Expect(err).ToNot(HaveOccurred())
 					Expect(p).ToNot(BeNil())
 					Expect(p.frames).ToNot(ContainElement(&wire.PingFrame{}))
@@ -859,7 +887,7 @@ var _ = Describe("Packet packer", func() {
 						return nil, 0
 					})
 					expectAppendStreamFrames()
-					_, err := packer.PackPacket()
+					_, err := packer.PackPacket(false)
 					Expect(err).ToNot(HaveOccurred())
 					// now reduce the maxPacketSize
 					packer.HandleTransportParameters(&wire.TransportParameters{
@@ -870,7 +898,7 @@ var _ = Describe("Packet packer", func() {
 						return nil, 0
 					})
 					expectAppendStreamFrames()
-					_, err = packer.PackPacket()
+					_, err = packer.PackPacket(false)
 					Expect(err).ToNot(HaveOccurred())
 				})
 
@@ -885,7 +913,7 @@ var _ = Describe("Packet packer", func() {
 						return nil, 0
 					})
 					expectAppendStreamFrames()
-					_, err := packer.PackPacket()
+					_, err := packer.PackPacket(false)
 					Expect(err).ToNot(HaveOccurred())
 					// now try to increase the maxPacketSize
 					packer.HandleTransportParameters(&wire.TransportParameters{
@@ -896,7 +924,7 @@ var _ = Describe("Packet packer", func() {
 						return nil, 0
 					})
 					expectAppendStreamFrames()
-					_, err = packer.PackPacket()
+					_, err = packer.PackPacket(false)
 					Expect(err).ToNot(HaveOccurred())
 				})
 			})
@@ -913,7 +941,7 @@ var _ = Describe("Packet packer", func() {
 						return nil, 0
 					})
 					expectAppendStreamFrames()
-					_, err := packer.PackPacket()
+					_, err := packer.PackPacket(false)
 					Expect(err).ToNot(HaveOccurred())
 					// now reduce the maxPacketSize
 					const packetSizeIncrease = 50
@@ -923,7 +951,7 @@ var _ = Describe("Packet packer", func() {
 						return nil, 0
 					})
 					expectAppendStreamFrames()
-					_, err = packer.PackPacket()
+					_, err = packer.PackPacket(false)
 					Expect(err).ToNot(HaveOccurred())
 				})
 			})
@@ -943,7 +971,7 @@ var _ = Describe("Packet packer", func() {
 				sealingManager.EXPECT().GetInitialSealer().Return(nil, handshake.ErrKeysDropped)
 				sealingManager.EXPECT().GetHandshakeSealer().Return(getSealer(), nil)
 				sealingManager.EXPECT().Get1RTTSealer().Return(nil, handshake.ErrKeysNotYetAvailable)
-				p, err := packer.PackCoalescedPacket()
+				p, err := packer.PackCoalescedPacket(false)
 				Expect(err).ToNot(HaveOccurred())
 				Expect(p).ToNot(BeNil())
 				parsePacket(p.buffer.Data)
@@ -962,7 +990,7 @@ var _ = Describe("Packet packer", func() {
 				initialStream.EXPECT().PopCryptoFrame(gomock.Any()).DoAndReturn(func(size protocol.ByteCount) *wire.CryptoFrame {
 					return &wire.CryptoFrame{Offset: 0x42, Data: []byte("initial")}
 				})
-				p, err := packer.PackCoalescedPacket()
+				p, err := packer.PackCoalescedPacket(false)
 				Expect(err).ToNot(HaveOccurred())
 				Expect(p.buffer.Len()).To(BeNumerically(">=", protocol.MinInitialPacketSize))
 				Expect(p.buffer.Len()).To(BeEquivalentTo(maxPacketSize))
@@ -991,7 +1019,7 @@ var _ = Describe("Packet packer", func() {
 					Expect(f.Length(packer.version)).To(Equal(size))
 					return f
 				})
-				p, err := packer.PackCoalescedPacket()
+				p, err := packer.PackCoalescedPacket(false)
 				Expect(err).ToNot(HaveOccurred())
 				Expect(p.packets).To(HaveLen(1))
 				Expect(p.packets[0].frames).To(HaveLen(1))
@@ -1018,7 +1046,7 @@ var _ = Describe("Packet packer", func() {
 				handshakeStream.EXPECT().PopCryptoFrame(gomock.Any()).DoAndReturn(func(size protocol.ByteCount) *wire.CryptoFrame {
 					return &wire.CryptoFrame{Offset: 0x1337, Data: []byte("handshake")}
 				})
-				p, err := packer.PackCoalescedPacket()
+				p, err := packer.PackCoalescedPacket(false)
 				Expect(err).ToNot(HaveOccurred())
 				Expect(p.buffer.Len()).To(BeEquivalentTo(packer.maxPacketSize))
 				Expect(p.packets).To(HaveLen(2))
@@ -1050,7 +1078,7 @@ var _ = Describe("Packet packer", func() {
 				})
 				handshakeStream.EXPECT().HasData()
 				packer.retransmissionQueue.AddHandshake(&wire.PingFrame{})
-				p, err := packer.PackCoalescedPacket()
+				p, err := packer.PackCoalescedPacket(false)
 				Expect(err).ToNot(HaveOccurred())
 				Expect(p.buffer.Len()).To(BeEquivalentTo(packer.maxPacketSize))
 				Expect(p.packets).To(HaveLen(2))
@@ -1079,7 +1107,7 @@ var _ = Describe("Packet packer", func() {
 				handshakeStream.EXPECT().HasData()
 				packer.retransmissionQueue.AddInitial(&wire.PingFrame{})
 				packer.retransmissionQueue.AddHandshake(&wire.PingFrame{})
-				p, err := packer.PackCoalescedPacket()
+				p, err := packer.PackCoalescedPacket(false)
 				Expect(err).ToNot(HaveOccurred())
 				Expect(p.buffer.Len()).To(BeEquivalentTo(packer.maxPacketSize))
 				Expect(p.packets).To(HaveLen(2))
@@ -1112,7 +1140,7 @@ var _ = Describe("Packet packer", func() {
 				expectAppendStreamFrames()
 				framer.EXPECT().HasData().Return(true)
 				packer.retransmissionQueue.AddAppData(&wire.PingFrame{})
-				p, err := packer.PackCoalescedPacket()
+				p, err := packer.PackCoalescedPacket(false)
 				Expect(err).ToNot(HaveOccurred())
 				Expect(p.buffer.Len()).To(BeEquivalentTo(packer.maxPacketSize))
 				Expect(p.packets).To(HaveLen(2))
@@ -1147,7 +1175,7 @@ var _ = Describe("Packet packer", func() {
 				})
 				expectAppendControlFrames()
 				expectAppendStreamFrames(ackhandler.Frame{Frame: &wire.StreamFrame{Data: []byte("foobar")}})
-				p, err := packer.PackCoalescedPacket()
+				p, err := packer.PackCoalescedPacket(false)
 				Expect(err).ToNot(HaveOccurred())
 				Expect(p.buffer.Len()).To(BeNumerically(">=", protocol.MinInitialPacketSize))
 				Expect(p.buffer.Len()).To(BeEquivalentTo(maxPacketSize))
@@ -1181,7 +1209,7 @@ var _ = Describe("Packet packer", func() {
 				})
 				expectAppendControlFrames()
 				expectAppendStreamFrames(ackhandler.Frame{Frame: &wire.StreamFrame{Data: []byte("foobar")}})
-				p, err := packer.PackCoalescedPacket()
+				p, err := packer.PackCoalescedPacket(false)
 				Expect(err).ToNot(HaveOccurred())
 				Expect(p.buffer.Len()).To(BeNumerically("<", 100))
 				Expect(p.packets).To(HaveLen(2))
@@ -1215,7 +1243,7 @@ var _ = Describe("Packet packer", func() {
 					Expect(f.Length(packer.version)).To(Equal(s))
 					return f
 				})
-				p, err := packer.PackCoalescedPacket()
+				p, err := packer.PackCoalescedPacket(false)
 				Expect(err).ToNot(HaveOccurred())
 				Expect(p.packets).To(HaveLen(1))
 				Expect(p.packets[0].EncryptionLevel()).To(Equal(protocol.EncryptionHandshake))
@@ -1233,7 +1261,7 @@ var _ = Describe("Packet packer", func() {
 				packer.retransmissionQueue.AddHandshake(&wire.PingFrame{})
 				handshakeStream.EXPECT().HasData()
 				ackFramer.EXPECT().GetAckFrame(protocol.EncryptionHandshake, false)
-				packet, err := packer.PackCoalescedPacket()
+				packet, err := packer.PackCoalescedPacket(false)
 				Expect(err).ToNot(HaveOccurred())
 				Expect(packet).ToNot(BeNil())
 				Expect(packet.packets).To(HaveLen(1))
@@ -1273,7 +1301,7 @@ var _ = Describe("Packet packer", func() {
 				sealingManager.EXPECT().Get1RTTSealer().Return(nil, handshake.ErrKeysNotYetAvailable)
 				ackFramer.EXPECT().GetAckFrame(protocol.EncryptionInitial, false)
 				initialStream.EXPECT().HasData()
-				p, err := packer.PackCoalescedPacket()
+				p, err := packer.PackCoalescedPacket(false)
 				Expect(err).ToNot(HaveOccurred())
 				Expect(p.packets).To(HaveLen(1))
 				Expect(p.packets[0].EncryptionLevel()).To(Equal(protocol.EncryptionInitial))
@@ -1290,7 +1318,7 @@ var _ = Describe("Packet packer", func() {
 				sealingManager.EXPECT().Get1RTTSealer().Return(nil, handshake.ErrKeysNotYetAvailable)
 				pnManager.EXPECT().PeekPacketNumber(protocol.EncryptionInitial).Return(protocol.PacketNumber(0x42), protocol.PacketNumberLen2)
 				pnManager.EXPECT().PopPacketNumber(protocol.EncryptionInitial).Return(protocol.PacketNumber(0x42))
-				p, err := packer.PackCoalescedPacket()
+				p, err := packer.PackCoalescedPacket(false)
 				Expect(err).ToNot(HaveOccurred())
 				Expect(p.packets).To(HaveLen(1))
 				Expect(p.packets[0].ack).To(Equal(ack))
@@ -1302,7 +1330,7 @@ var _ = Describe("Packet packer", func() {
 				sealingManager.EXPECT().Get1RTTSealer().Return(nil, handshake.ErrKeysNotYetAvailable)
 				initialStream.EXPECT().HasData()
 				ackFramer.EXPECT().GetAckFrame(protocol.EncryptionInitial, true)
-				p, err := packer.PackCoalescedPacket()
+				p, err := packer.PackCoalescedPacket(false)
 				Expect(err).ToNot(HaveOccurred())
 				Expect(p).To(BeNil())
 			})
@@ -1318,7 +1346,7 @@ var _ = Describe("Packet packer", func() {
 				sealingManager.EXPECT().Get1RTTSealer().Return(nil, handshake.ErrKeysNotYetAvailable)
 				pnManager.EXPECT().PeekPacketNumber(protocol.EncryptionHandshake).Return(protocol.PacketNumber(0x42), protocol.PacketNumberLen2)
 				pnManager.EXPECT().PopPacketNumber(protocol.EncryptionHandshake).Return(protocol.PacketNumber(0x42))
-				p, err := packer.PackCoalescedPacket()
+				p, err := packer.PackCoalescedPacket(false)
 				Expect(err).ToNot(HaveOccurred())
 				Expect(p.packets).To(HaveLen(1))
 				Expect(p.packets[0].ack).To(Equal(ack))
@@ -1341,7 +1369,7 @@ var _ = Describe("Packet packer", func() {
 					initialStream.EXPECT().HasData().Return(true).Times(2)
 					initialStream.EXPECT().PopCryptoFrame(gomock.Any()).Return(f)
 					packer.perspective = protocol.PerspectiveClient
-					p, err := packer.PackCoalescedPacket()
+					p, err := packer.PackCoalescedPacket(false)
 					Expect(err).ToNot(HaveOccurred())
 					Expect(p.buffer.Len()).To(BeNumerically(">=", protocol.MinInitialPacketSize))
 					Expect(p.buffer.Len()).To(BeEquivalentTo(maxPacketSize))
@@ -1367,7 +1395,7 @@ var _ = Describe("Packet packer", func() {
 				initialStream.EXPECT().PopCryptoFrame(gomock.Any()).Return(f)
 				packer.version = protocol.VersionTLS
 				packer.perspective = protocol.PerspectiveClient
-				p, err := packer.PackCoalescedPacket()
+				p, err := packer.PackCoalescedPacket(false)
 				Expect(err).ToNot(HaveOccurred())
 				Expect(p.packets).To(HaveLen(1))
 				Expect(p.packets[0].ack).To(Equal(ack))