diff --git a/vendor/google.golang.org/grpc/internal/transport/handler_server.go b/vendor/google.golang.org/grpc/internal/transport/handler_server.go
index 73b41ea..78f9ddc 100644
--- a/vendor/google.golang.org/grpc/internal/transport/handler_server.go
+++ b/vendor/google.golang.org/grpc/internal/transport/handler_server.go
@@ -24,6 +24,7 @@
 package transport
 
 import (
+	"bytes"
 	"context"
 	"errors"
 	"fmt"
@@ -63,9 +64,6 @@
 	if _, ok := w.(http.Flusher); !ok {
 		return nil, errors.New("gRPC requires a ResponseWriter supporting http.Flusher")
 	}
-	if _, ok := w.(http.CloseNotifier); !ok {
-		return nil, errors.New("gRPC requires a ResponseWriter supporting http.CloseNotifier")
-	}
 
 	st := &serverHandlerTransport{
 		rw:             w,
@@ -176,17 +174,11 @@
 
 // do runs fn in the ServeHTTP goroutine.
 func (ht *serverHandlerTransport) do(fn func()) error {
-	// Avoid a panic writing to closed channel. Imperfect but maybe good enough.
 	select {
 	case <-ht.closedCh:
 		return ErrConnClosing
-	default:
-		select {
-		case ht.writes <- fn:
-			return nil
-		case <-ht.closedCh:
-			return ErrConnClosing
-		}
+	case ht.writes <- fn:
+		return nil
 	}
 }
 
@@ -237,7 +229,6 @@
 		if ht.stats != nil {
 			ht.stats.HandleRPC(s.Context(), &stats.OutTrailer{})
 		}
-		close(ht.writes)
 	}
 	ht.Close()
 	return err
@@ -315,19 +306,13 @@
 		ctx, cancel = context.WithCancel(ctx)
 	}
 
-	// requestOver is closed when either the request's context is done
-	// or the status has been written via WriteStatus.
+	// requestOver is closed when the status has been written via WriteStatus.
 	requestOver := make(chan struct{})
-
-	// clientGone receives a single value if peer is gone, either
-	// because the underlying connection is dead or because the
-	// peer sends an http2 RST_STREAM.
-	clientGone := ht.rw.(http.CloseNotifier).CloseNotify()
 	go func() {
 		select {
 		case <-requestOver:
 		case <-ht.closedCh:
-		case <-clientGone:
+		case <-ht.req.Context().Done():
 		}
 		cancel()
 		ht.Close()
@@ -363,7 +348,7 @@
 		ht.stats.HandleRPC(s.ctx, inHeader)
 	}
 	s.trReader = &transportReader{
-		reader:        &recvBufferReader{ctx: s.ctx, ctxDone: s.ctx.Done(), recv: s.buf},
+		reader:        &recvBufferReader{ctx: s.ctx, ctxDone: s.ctx.Done(), recv: s.buf, freeBuffer: func(*bytes.Buffer) {}},
 		windowHandler: func(int) {},
 	}
 
@@ -377,7 +362,7 @@
 		for buf := make([]byte, readSize); ; {
 			n, err := req.Body.Read(buf)
 			if n > 0 {
-				s.buf.put(recvMsg{data: buf[:n:n]})
+				s.buf.put(recvMsg{buffer: bytes.NewBuffer(buf[:n:n])})
 				buf = buf[n:]
 			}
 			if err != nil {
@@ -407,10 +392,7 @@
 func (ht *serverHandlerTransport) runStream() {
 	for {
 		select {
-		case fn, ok := <-ht.writes:
-			if !ok {
-				return
-			}
+		case fn := <-ht.writes:
 			fn()
 		case <-ht.closedCh:
 			return
diff --git a/vendor/google.golang.org/grpc/internal/transport/http2_client.go b/vendor/google.golang.org/grpc/internal/transport/http2_client.go
index ff8f4db..c96178d 100644
--- a/vendor/google.golang.org/grpc/internal/transport/http2_client.go
+++ b/vendor/google.golang.org/grpc/internal/transport/http2_client.go
@@ -117,6 +117,8 @@
 
 	onGoAway func(GoAwayReason)
 	onClose  func()
+
+	bufferPool *bufferPool
 }
 
 func dial(ctx context.Context, fn func(context.Context, string) (net.Conn, error), addr string) (net.Conn, error) {
@@ -249,6 +251,7 @@
 		onGoAway:              onGoAway,
 		onClose:               onClose,
 		keepaliveEnabled:      keepaliveEnabled,
+		bufferPool:            newBufferPool(),
 	}
 	t.controlBuf = newControlBuffer(t.ctxDone)
 	if opts.InitialWindowSize >= defaultWindowSize {
@@ -367,6 +370,7 @@
 			closeStream: func(err error) {
 				t.CloseStream(s, err)
 			},
+			freeBuffer: t.bufferPool.put,
 		},
 		windowHandler: func(n int) {
 			t.updateWindow(s, uint32(n))
@@ -437,6 +441,15 @@
 
 	if md, added, ok := metadata.FromOutgoingContextRaw(ctx); ok {
 		var k string
+		for k, vv := range md {
+			// HTTP doesn't allow you to set pseudoheaders after non pseudoheaders were set.
+			if isReservedHeader(k) {
+				continue
+			}
+			for _, v := range vv {
+				headerFields = append(headerFields, hpack.HeaderField{Name: k, Value: encodeMetadataHeader(k, v)})
+			}
+		}
 		for _, vv := range added {
 			for i, v := range vv {
 				if i%2 == 0 {
@@ -450,15 +463,6 @@
 				headerFields = append(headerFields, hpack.HeaderField{Name: strings.ToLower(k), Value: encodeMetadataHeader(k, v)})
 			}
 		}
-		for k, vv := range md {
-			// HTTP doesn't allow you to set pseudoheaders after non pseudoheaders were set.
-			if isReservedHeader(k) {
-				continue
-			}
-			for _, v := range vv {
-				headerFields = append(headerFields, hpack.HeaderField{Name: k, Value: encodeMetadataHeader(k, v)})
-			}
-		}
 	}
 	if md, ok := t.md.(*metadata.MD); ok {
 		for k, vv := range *md {
@@ -549,7 +553,7 @@
 		s.write(recvMsg{err: err})
 		close(s.done)
 		// If headerChan isn't closed, then close it.
-		if atomic.SwapUint32(&s.headerDone, 1) == 0 {
+		if atomic.CompareAndSwapUint32(&s.headerChanClosed, 0, 1) {
 			close(s.headerChan)
 		}
 
@@ -713,7 +717,7 @@
 		s.write(recvMsg{err: err})
 	}
 	// If headerChan isn't closed, then close it.
-	if atomic.SwapUint32(&s.headerDone, 1) == 0 {
+	if atomic.CompareAndSwapUint32(&s.headerChanClosed, 0, 1) {
 		s.noHeaders = true
 		close(s.headerChan)
 	}
@@ -794,21 +798,21 @@
 // stream is closed.  If there are no active streams, the transport is closed
 // immediately.  This does nothing if the transport is already draining or
 // closing.
-func (t *http2Client) GracefulClose() error {
+func (t *http2Client) GracefulClose() {
 	t.mu.Lock()
 	// Make sure we move to draining only from active.
 	if t.state == draining || t.state == closing {
 		t.mu.Unlock()
-		return nil
+		return
 	}
 	t.state = draining
 	active := len(t.activeStreams)
 	t.mu.Unlock()
 	if active == 0 {
-		return t.Close()
+		t.Close()
+		return
 	}
 	t.controlBuf.put(&incomingGoAway{})
-	return nil
 }
 
 // Write formats the data into HTTP2 data frame(s) and sends it out. The caller
@@ -946,9 +950,10 @@
 		// guarantee f.Data() is consumed before the arrival of next frame.
 		// Can this copy be eliminated?
 		if len(f.Data()) > 0 {
-			data := make([]byte, len(f.Data()))
-			copy(data, f.Data())
-			s.write(recvMsg{data: data})
+			buffer := t.bufferPool.get()
+			buffer.Reset()
+			buffer.Write(f.Data())
+			s.write(recvMsg{buffer: buffer})
 		}
 	}
 	// The server has closed the stream without sending trailers.  Record that
@@ -1140,16 +1145,26 @@
 	if !ok {
 		return
 	}
+	endStream := frame.StreamEnded()
 	atomic.StoreUint32(&s.bytesReceived, 1)
-	var state decodeState
-	if err := state.decodeHeader(frame); err != nil {
-		t.closeStream(s, err, true, http2.ErrCodeProtocol, status.New(codes.Internal, err.Error()), nil, false)
-		// Something wrong. Stops reading even when there is remaining.
+	initialHeader := atomic.LoadUint32(&s.headerChanClosed) == 0
+
+	if !initialHeader && !endStream {
+		// As specified by gRPC over HTTP2, a HEADERS frame (and associated CONTINUATION frames) can only appear at the start or end of a stream. Therefore, second HEADERS frame must have EOS bit set.
+		st := status.New(codes.Internal, "a HEADERS frame cannot appear in the middle of a stream")
+		t.closeStream(s, st.Err(), true, http2.ErrCodeProtocol, st, nil, false)
 		return
 	}
 
-	endStream := frame.StreamEnded()
-	var isHeader bool
+	state := &decodeState{}
+	// Initialize isGRPC value to be !initialHeader, since if a gRPC Response-Headers has already been received, then it means that the peer is speaking gRPC and we are in gRPC mode.
+	state.data.isGRPC = !initialHeader
+	if err := state.decodeHeader(frame); err != nil {
+		t.closeStream(s, err, true, http2.ErrCodeProtocol, status.Convert(err), nil, endStream)
+		return
+	}
+
+	isHeader := false
 	defer func() {
 		if t.statsHandler != nil {
 			if isHeader {
@@ -1167,29 +1182,33 @@
 			}
 		}
 	}()
-	// If headers haven't been received yet.
-	if atomic.SwapUint32(&s.headerDone, 1) == 0 {
+
+	// If headerChan hasn't been closed yet
+	if atomic.CompareAndSwapUint32(&s.headerChanClosed, 0, 1) {
 		if !endStream {
-			// Headers frame is not actually a trailers-only frame.
+			// HEADERS frame block carries a Response-Headers.
 			isHeader = true
 			// These values can be set without any synchronization because
 			// stream goroutine will read it only after seeing a closed
 			// headerChan which we'll close after setting this.
-			s.recvCompress = state.encoding
-			if len(state.mdata) > 0 {
-				s.header = state.mdata
+			s.recvCompress = state.data.encoding
+			if len(state.data.mdata) > 0 {
+				s.header = state.data.mdata
 			}
 		} else {
+			// HEADERS frame block carries a Trailers-Only.
 			s.noHeaders = true
 		}
 		close(s.headerChan)
 	}
+
 	if !endStream {
 		return
 	}
+
 	// if client received END_STREAM from server while stream was still active, send RST_STREAM
 	rst := s.getState() == streamActive
-	t.closeStream(s, io.EOF, rst, http2.ErrCodeNo, state.status(), state.mdata, true)
+	t.closeStream(s, io.EOF, rst, http2.ErrCodeNo, state.status(), state.data.mdata, true)
 }
 
 // reader runs as a separate goroutine in charge of reading data from network
@@ -1356,6 +1375,8 @@
 	return &s
 }
 
+func (t *http2Client) RemoteAddr() net.Addr { return t.remoteAddr }
+
 func (t *http2Client) IncrMsgSent() {
 	atomic.AddInt64(&t.czData.msgSent, 1)
 	atomic.StoreInt64(&t.czData.lastMsgSentTime, time.Now().UnixNano())
diff --git a/vendor/google.golang.org/grpc/internal/transport/http2_server.go b/vendor/google.golang.org/grpc/internal/transport/http2_server.go
index d038b2d..150b73e 100644
--- a/vendor/google.golang.org/grpc/internal/transport/http2_server.go
+++ b/vendor/google.golang.org/grpc/internal/transport/http2_server.go
@@ -35,9 +35,11 @@
 	"golang.org/x/net/http2"
 	"golang.org/x/net/http2/hpack"
 
+	spb "google.golang.org/genproto/googleapis/rpc/status"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/credentials"
 	"google.golang.org/grpc/grpclog"
+	"google.golang.org/grpc/internal"
 	"google.golang.org/grpc/internal/channelz"
 	"google.golang.org/grpc/internal/grpcrand"
 	"google.golang.org/grpc/keepalive"
@@ -55,6 +57,9 @@
 	// ErrHeaderListSizeLimitViolation indicates that the header list size is larger
 	// than the limit set by peer.
 	ErrHeaderListSizeLimitViolation = errors.New("transport: trying to send header list size larger than the limit set by peer")
+	// statusRawProto is a function to get to the raw status proto wrapped in a
+	// status.Status without a proto.Clone().
+	statusRawProto = internal.StatusRawProto.(func(*status.Status) *spb.Status)
 )
 
 // http2Server implements the ServerTransport interface with HTTP2.
@@ -119,6 +124,7 @@
 	// Fields below are for channelz metric collection.
 	channelzID int64 // channelz unique identification number
 	czData     *channelzData
+	bufferPool *bufferPool
 }
 
 // newHTTP2Server constructs a ServerTransport based on HTTP2. ConnectionError is
@@ -220,6 +226,7 @@
 		kep:               kep,
 		initialWindowSize: iwz,
 		czData:            new(channelzData),
+		bufferPool:        newBufferPool(),
 	}
 	t.controlBuf = newControlBuffer(t.ctxDone)
 	if dynamicWindow {
@@ -286,7 +293,9 @@
 // operateHeader takes action on the decoded headers.
 func (t *http2Server) operateHeaders(frame *http2.MetaHeadersFrame, handle func(*Stream), traceCtx func(context.Context, string) context.Context) (fatal bool) {
 	streamID := frame.Header().StreamID
-	state := decodeState{serverSide: true}
+	state := &decodeState{
+		serverSide: true,
+	}
 	if err := state.decodeHeader(frame); err != nil {
 		if se, ok := status.FromError(err); ok {
 			t.controlBuf.put(&cleanupStream{
@@ -305,16 +314,16 @@
 		st:             t,
 		buf:            buf,
 		fc:             &inFlow{limit: uint32(t.initialWindowSize)},
-		recvCompress:   state.encoding,
-		method:         state.method,
-		contentSubtype: state.contentSubtype,
+		recvCompress:   state.data.encoding,
+		method:         state.data.method,
+		contentSubtype: state.data.contentSubtype,
 	}
 	if frame.StreamEnded() {
 		// s is just created by the caller. No lock needed.
 		s.state = streamReadDone
 	}
-	if state.timeoutSet {
-		s.ctx, s.cancel = context.WithTimeout(t.ctx, state.timeout)
+	if state.data.timeoutSet {
+		s.ctx, s.cancel = context.WithTimeout(t.ctx, state.data.timeout)
 	} else {
 		s.ctx, s.cancel = context.WithCancel(t.ctx)
 	}
@@ -327,19 +336,19 @@
 	}
 	s.ctx = peer.NewContext(s.ctx, pr)
 	// Attach the received metadata to the context.
-	if len(state.mdata) > 0 {
-		s.ctx = metadata.NewIncomingContext(s.ctx, state.mdata)
+	if len(state.data.mdata) > 0 {
+		s.ctx = metadata.NewIncomingContext(s.ctx, state.data.mdata)
 	}
-	if state.statsTags != nil {
-		s.ctx = stats.SetIncomingTags(s.ctx, state.statsTags)
+	if state.data.statsTags != nil {
+		s.ctx = stats.SetIncomingTags(s.ctx, state.data.statsTags)
 	}
-	if state.statsTrace != nil {
-		s.ctx = stats.SetIncomingTrace(s.ctx, state.statsTrace)
+	if state.data.statsTrace != nil {
+		s.ctx = stats.SetIncomingTrace(s.ctx, state.data.statsTrace)
 	}
 	if t.inTapHandle != nil {
 		var err error
 		info := &tap.Info{
-			FullMethodName: state.method,
+			FullMethodName: state.data.method,
 		}
 		s.ctx, err = t.inTapHandle(s.ctx, info)
 		if err != nil {
@@ -403,9 +412,10 @@
 	s.wq = newWriteQuota(defaultWriteQuota, s.ctxDone)
 	s.trReader = &transportReader{
 		reader: &recvBufferReader{
-			ctx:     s.ctx,
-			ctxDone: s.ctxDone,
-			recv:    s.buf,
+			ctx:        s.ctx,
+			ctxDone:    s.ctxDone,
+			recv:       s.buf,
+			freeBuffer: t.bufferPool.put,
 		},
 		windowHandler: func(n int) {
 			t.updateWindow(s, uint32(n))
@@ -435,7 +445,7 @@
 				s := t.activeStreams[se.StreamID]
 				t.mu.Unlock()
 				if s != nil {
-					t.closeStream(s, true, se.Code, nil, false)
+					t.closeStream(s, true, se.Code, false)
 				} else {
 					t.controlBuf.put(&cleanupStream{
 						streamID: se.StreamID,
@@ -577,7 +587,7 @@
 	}
 	if size > 0 {
 		if err := s.fc.onData(size); err != nil {
-			t.closeStream(s, true, http2.ErrCodeFlowControl, nil, false)
+			t.closeStream(s, true, http2.ErrCodeFlowControl, false)
 			return
 		}
 		if f.Header().Flags.Has(http2.FlagDataPadded) {
@@ -589,9 +599,10 @@
 		// guarantee f.Data() is consumed before the arrival of next frame.
 		// Can this copy be eliminated?
 		if len(f.Data()) > 0 {
-			data := make([]byte, len(f.Data()))
-			copy(data, f.Data())
-			s.write(recvMsg{data: data})
+			buffer := t.bufferPool.get()
+			buffer.Reset()
+			buffer.Write(f.Data())
+			s.write(recvMsg{buffer: buffer})
 		}
 	}
 	if f.Header().Flags.Has(http2.FlagDataEndStream) {
@@ -602,11 +613,18 @@
 }
 
 func (t *http2Server) handleRSTStream(f *http2.RSTStreamFrame) {
-	s, ok := t.getStream(f)
-	if !ok {
+	// If the stream is not deleted from the transport's active streams map, then do a regular close stream.
+	if s, ok := t.getStream(f); ok {
+		t.closeStream(s, false, 0, false)
 		return
 	}
-	t.closeStream(s, false, 0, nil, false)
+	// If the stream is already deleted from the active streams map, then put a cleanupStream item into controlbuf to delete the stream from loopy writer's established streams map.
+	t.controlBuf.put(&cleanupStream{
+		streamID: f.Header().StreamID,
+		rst:      false,
+		rstCode:  0,
+		onWrite:  func() {},
+	})
 }
 
 func (t *http2Server) handleSettings(f *http2.SettingsFrame) {
@@ -770,7 +788,7 @@
 		if err != nil {
 			return err
 		}
-		t.closeStream(s, true, http2.ErrCodeInternal, nil, false)
+		t.closeStream(s, true, http2.ErrCodeInternal, false)
 		return ErrHeaderListSizeLimitViolation
 	}
 	if t.stats != nil {
@@ -808,7 +826,7 @@
 	headerFields = append(headerFields, hpack.HeaderField{Name: "grpc-status", Value: strconv.Itoa(int(st.Code()))})
 	headerFields = append(headerFields, hpack.HeaderField{Name: "grpc-message", Value: encodeGrpcMessage(st.Message())})
 
-	if p := st.Proto(); p != nil && len(p.Details) > 0 {
+	if p := statusRawProto(st); p != nil && len(p.Details) > 0 {
 		stBytes, err := proto.Marshal(p)
 		if err != nil {
 			// TODO: return error instead, when callers are able to handle it.
@@ -834,10 +852,12 @@
 		if err != nil {
 			return err
 		}
-		t.closeStream(s, true, http2.ErrCodeInternal, nil, false)
+		t.closeStream(s, true, http2.ErrCodeInternal, false)
 		return ErrHeaderListSizeLimitViolation
 	}
-	t.closeStream(s, false, 0, trailingHeader, true)
+	// Send a RST_STREAM after the trailers if the client has not already half-closed.
+	rst := s.getState() == streamActive
+	t.finishStream(s, rst, http2.ErrCodeNo, trailingHeader, true)
 	if t.stats != nil {
 		t.stats.HandleRPC(s.Context(), &stats.OutTrailer{})
 	}
@@ -849,6 +869,9 @@
 func (t *http2Server) Write(s *Stream, hdr []byte, data []byte, opts *Options) error {
 	if !s.isHeaderSent() { // Headers haven't been written yet.
 		if err := t.WriteHeader(s, nil); err != nil {
+			if _, ok := err.(ConnectionError); ok {
+				return err
+			}
 			// TODO(mmukhi, dfawley): Make sure this is the right code to return.
 			return status.Errorf(codes.Internal, "transport: %v", err)
 		}
@@ -1006,15 +1029,17 @@
 
 // deleteStream deletes the stream s from transport's active streams.
 func (t *http2Server) deleteStream(s *Stream, eosReceived bool) {
-	t.mu.Lock()
-	if _, ok := t.activeStreams[s.id]; !ok {
-		t.mu.Unlock()
-		return
-	}
+	// In case stream sending and receiving are invoked in separate
+	// goroutines (e.g., bi-directional streaming), cancel needs to be
+	// called to interrupt the potential blocking on other goroutines.
+	s.cancel()
 
-	delete(t.activeStreams, s.id)
-	if len(t.activeStreams) == 0 {
-		t.idle = time.Now()
+	t.mu.Lock()
+	if _, ok := t.activeStreams[s.id]; ok {
+		delete(t.activeStreams, s.id)
+		if len(t.activeStreams) == 0 {
+			t.idle = time.Now()
+		}
 	}
 	t.mu.Unlock()
 
@@ -1027,51 +1052,36 @@
 	}
 }
 
-// closeStream clears the footprint of a stream when the stream is not needed
-// any more.
-func (t *http2Server) closeStream(s *Stream, rst bool, rstCode http2.ErrCode, hdr *headerFrame, eosReceived bool) {
-	// Mark the stream as done
+// finishStream closes the stream and puts the trailing headerFrame into controlbuf.
+func (t *http2Server) finishStream(s *Stream, rst bool, rstCode http2.ErrCode, hdr *headerFrame, eosReceived bool) {
 	oldState := s.swapState(streamDone)
+	if oldState == streamDone {
+		// If the stream was already done, return.
+		return
+	}
 
-	// In case stream sending and receiving are invoked in separate
-	// goroutines (e.g., bi-directional streaming), cancel needs to be
-	// called to interrupt the potential blocking on other goroutines.
-	s.cancel()
+	hdr.cleanup = &cleanupStream{
+		streamID: s.id,
+		rst:      rst,
+		rstCode:  rstCode,
+		onWrite: func() {
+			t.deleteStream(s, eosReceived)
+		},
+	}
+	t.controlBuf.put(hdr)
+}
 
-	// Deletes the stream from active streams
+// closeStream clears the footprint of a stream when the stream is not needed any more.
+func (t *http2Server) closeStream(s *Stream, rst bool, rstCode http2.ErrCode, eosReceived bool) {
+	s.swapState(streamDone)
 	t.deleteStream(s, eosReceived)
 
-	cleanup := &cleanupStream{
+	t.controlBuf.put(&cleanupStream{
 		streamID: s.id,
 		rst:      rst,
 		rstCode:  rstCode,
 		onWrite:  func() {},
-	}
-
-	// No trailer. Puts cleanupFrame into transport's control buffer.
-	if hdr == nil {
-		t.controlBuf.put(cleanup)
-		return
-	}
-
-	// We do the check here, because of the following scenario:
-	// 1. closeStream is called first with a trailer. A trailer item with a piggybacked cleanup item
-	// is put to control buffer.
-	// 2. Loopy writer is waiting on a stream quota. It will never get it because client errored at
-	// some point. So loopy can't act on trailer
-	// 3. Client sends a RST_STREAM due to the error. Then closeStream is called without a trailer as
-	// the result of the received RST_STREAM.
-	// If we do this check at the beginning of the closeStream, then we won't put a cleanup item in
-	// response to received RST_STREAM into the control buffer and outStream in loopy writer will
-	// never get cleaned up.
-
-	// If the stream is already done, don't send the trailer.
-	if oldState == streamDone {
-		return
-	}
-
-	hdr.cleanup = cleanup
-	t.controlBuf.put(hdr)
+	})
 }
 
 func (t *http2Server) RemoteAddr() net.Addr {
diff --git a/vendor/google.golang.org/grpc/internal/transport/http_util.go b/vendor/google.golang.org/grpc/internal/transport/http_util.go
index 77a2cfa..9d21286 100644
--- a/vendor/google.golang.org/grpc/internal/transport/http_util.go
+++ b/vendor/google.golang.org/grpc/internal/transport/http_util.go
@@ -78,7 +78,8 @@
 		codes.ResourceExhausted: http2.ErrCodeEnhanceYourCalm,
 		codes.PermissionDenied:  http2.ErrCodeInadequateSecurity,
 	}
-	httpStatusConvTab = map[int]codes.Code{
+	// HTTPStatusConvTab is the HTTP status code to gRPC error code conversion table.
+	HTTPStatusConvTab = map[int]codes.Code{
 		// 400 Bad Request - INTERNAL.
 		http.StatusBadRequest: codes.Internal,
 		// 401 Unauthorized  - UNAUTHENTICATED.
@@ -98,9 +99,7 @@
 	}
 )
 
-// Records the states during HPACK decoding. Must be reset once the
-// decoding of the entire headers are finished.
-type decodeState struct {
+type parsedHeaderData struct {
 	encoding string
 	// statusGen caches the stream status received from the trailer the server
 	// sent.  Client side only.  Do not access directly.  After all trailers are
@@ -120,8 +119,30 @@
 	statsTags      []byte
 	statsTrace     []byte
 	contentSubtype string
+
+	// isGRPC field indicates whether the peer is speaking gRPC (otherwise HTTP).
+	//
+	// We are in gRPC mode (peer speaking gRPC) if:
+	// 	* We are client side and have already received a HEADER frame that indicates gRPC peer.
+	//  * The header contains valid  a content-type, i.e. a string starts with "application/grpc"
+	// And we should handle error specific to gRPC.
+	//
+	// Otherwise (i.e. a content-type string starts without "application/grpc", or does not exist), we
+	// are in HTTP fallback mode, and should handle error specific to HTTP.
+	isGRPC         bool
+	grpcErr        error
+	httpErr        error
+	contentTypeErr string
+}
+
+// decodeState configures decoding criteria and records the decoded data.
+type decodeState struct {
 	// whether decoding on server side or not
 	serverSide bool
+
+	// Records the states during HPACK decoding. It will be filled with info parsed from HTTP HEADERS
+	// frame once decodeHeader function has been invoked and returned.
+	data parsedHeaderData
 }
 
 // isReservedHeader checks whether hdr belongs to HTTP2 headers
@@ -202,11 +223,11 @@
 }
 
 func (d *decodeState) status() *status.Status {
-	if d.statusGen == nil {
+	if d.data.statusGen == nil {
 		// No status-details were provided; generate status using code/msg.
-		d.statusGen = status.New(codes.Code(int32(*(d.rawStatusCode))), d.rawStatusMsg)
+		d.data.statusGen = status.New(codes.Code(int32(*(d.data.rawStatusCode))), d.data.rawStatusMsg)
 	}
-	return d.statusGen
+	return d.data.statusGen
 }
 
 const binHdrSuffix = "-bin"
@@ -244,113 +265,146 @@
 	if frame.Truncated {
 		return status.Error(codes.Internal, "peer header list size exceeded limit")
 	}
+
 	for _, hf := range frame.Fields {
-		if err := d.processHeaderField(hf); err != nil {
-			return err
+		d.processHeaderField(hf)
+	}
+
+	if d.data.isGRPC {
+		if d.data.grpcErr != nil {
+			return d.data.grpcErr
 		}
-	}
-
-	if d.serverSide {
+		if d.serverSide {
+			return nil
+		}
+		if d.data.rawStatusCode == nil && d.data.statusGen == nil {
+			// gRPC status doesn't exist.
+			// Set rawStatusCode to be unknown and return nil error.
+			// So that, if the stream has ended this Unknown status
+			// will be propagated to the user.
+			// Otherwise, it will be ignored. In which case, status from
+			// a later trailer, that has StreamEnded flag set, is propagated.
+			code := int(codes.Unknown)
+			d.data.rawStatusCode = &code
+		}
 		return nil
 	}
 
-	// If grpc status exists, no need to check further.
-	if d.rawStatusCode != nil || d.statusGen != nil {
-		return nil
+	// HTTP fallback mode
+	if d.data.httpErr != nil {
+		return d.data.httpErr
 	}
 
-	// If grpc status doesn't exist and http status doesn't exist,
-	// then it's a malformed header.
-	if d.httpStatus == nil {
-		return status.Error(codes.Internal, "malformed header: doesn't contain status(gRPC or HTTP)")
-	}
+	var (
+		code = codes.Internal // when header does not include HTTP status, return INTERNAL
+		ok   bool
+	)
 
-	if *(d.httpStatus) != http.StatusOK {
-		code, ok := httpStatusConvTab[*(d.httpStatus)]
+	if d.data.httpStatus != nil {
+		code, ok = HTTPStatusConvTab[*(d.data.httpStatus)]
 		if !ok {
 			code = codes.Unknown
 		}
-		return status.Error(code, http.StatusText(*(d.httpStatus)))
 	}
 
-	// gRPC status doesn't exist and http status is OK.
-	// Set rawStatusCode to be unknown and return nil error.
-	// So that, if the stream has ended this Unknown status
-	// will be propagated to the user.
-	// Otherwise, it will be ignored. In which case, status from
-	// a later trailer, that has StreamEnded flag set, is propagated.
-	code := int(codes.Unknown)
-	d.rawStatusCode = &code
-	return nil
+	return status.Error(code, d.constructHTTPErrMsg())
+}
+
+// constructErrMsg constructs error message to be returned in HTTP fallback mode.
+// Format: HTTP status code and its corresponding message + content-type error message.
+func (d *decodeState) constructHTTPErrMsg() string {
+	var errMsgs []string
+
+	if d.data.httpStatus == nil {
+		errMsgs = append(errMsgs, "malformed header: missing HTTP status")
+	} else {
+		errMsgs = append(errMsgs, fmt.Sprintf("%s: HTTP status code %d", http.StatusText(*(d.data.httpStatus)), *d.data.httpStatus))
+	}
+
+	if d.data.contentTypeErr == "" {
+		errMsgs = append(errMsgs, "transport: missing content-type field")
+	} else {
+		errMsgs = append(errMsgs, d.data.contentTypeErr)
+	}
+
+	return strings.Join(errMsgs, "; ")
 }
 
 func (d *decodeState) addMetadata(k, v string) {
-	if d.mdata == nil {
-		d.mdata = make(map[string][]string)
+	if d.data.mdata == nil {
+		d.data.mdata = make(map[string][]string)
 	}
-	d.mdata[k] = append(d.mdata[k], v)
+	d.data.mdata[k] = append(d.data.mdata[k], v)
 }
 
-func (d *decodeState) processHeaderField(f hpack.HeaderField) error {
+func (d *decodeState) processHeaderField(f hpack.HeaderField) {
 	switch f.Name {
 	case "content-type":
 		contentSubtype, validContentType := contentSubtype(f.Value)
 		if !validContentType {
-			return status.Errorf(codes.Internal, "transport: received the unexpected content-type %q", f.Value)
+			d.data.contentTypeErr = fmt.Sprintf("transport: received the unexpected content-type %q", f.Value)
+			return
 		}
-		d.contentSubtype = contentSubtype
+		d.data.contentSubtype = contentSubtype
 		// TODO: do we want to propagate the whole content-type in the metadata,
 		// or come up with a way to just propagate the content-subtype if it was set?
 		// ie {"content-type": "application/grpc+proto"} or {"content-subtype": "proto"}
 		// in the metadata?
 		d.addMetadata(f.Name, f.Value)
+		d.data.isGRPC = true
 	case "grpc-encoding":
-		d.encoding = f.Value
+		d.data.encoding = f.Value
 	case "grpc-status":
 		code, err := strconv.Atoi(f.Value)
 		if err != nil {
-			return status.Errorf(codes.Internal, "transport: malformed grpc-status: %v", err)
+			d.data.grpcErr = status.Errorf(codes.Internal, "transport: malformed grpc-status: %v", err)
+			return
 		}
-		d.rawStatusCode = &code
+		d.data.rawStatusCode = &code
 	case "grpc-message":
-		d.rawStatusMsg = decodeGrpcMessage(f.Value)
+		d.data.rawStatusMsg = decodeGrpcMessage(f.Value)
 	case "grpc-status-details-bin":
 		v, err := decodeBinHeader(f.Value)
 		if err != nil {
-			return status.Errorf(codes.Internal, "transport: malformed grpc-status-details-bin: %v", err)
+			d.data.grpcErr = status.Errorf(codes.Internal, "transport: malformed grpc-status-details-bin: %v", err)
+			return
 		}
 		s := &spb.Status{}
 		if err := proto.Unmarshal(v, s); err != nil {
-			return status.Errorf(codes.Internal, "transport: malformed grpc-status-details-bin: %v", err)
+			d.data.grpcErr = status.Errorf(codes.Internal, "transport: malformed grpc-status-details-bin: %v", err)
+			return
 		}
-		d.statusGen = status.FromProto(s)
+		d.data.statusGen = status.FromProto(s)
 	case "grpc-timeout":
-		d.timeoutSet = true
+		d.data.timeoutSet = true
 		var err error
-		if d.timeout, err = decodeTimeout(f.Value); err != nil {
-			return status.Errorf(codes.Internal, "transport: malformed time-out: %v", err)
+		if d.data.timeout, err = decodeTimeout(f.Value); err != nil {
+			d.data.grpcErr = status.Errorf(codes.Internal, "transport: malformed time-out: %v", err)
 		}
 	case ":path":
-		d.method = f.Value
+		d.data.method = f.Value
 	case ":status":
 		code, err := strconv.Atoi(f.Value)
 		if err != nil {
-			return status.Errorf(codes.Internal, "transport: malformed http-status: %v", err)
+			d.data.httpErr = status.Errorf(codes.Internal, "transport: malformed http-status: %v", err)
+			return
 		}
-		d.httpStatus = &code
+		d.data.httpStatus = &code
 	case "grpc-tags-bin":
 		v, err := decodeBinHeader(f.Value)
 		if err != nil {
-			return status.Errorf(codes.Internal, "transport: malformed grpc-tags-bin: %v", err)
+			d.data.grpcErr = status.Errorf(codes.Internal, "transport: malformed grpc-tags-bin: %v", err)
+			return
 		}
-		d.statsTags = v
+		d.data.statsTags = v
 		d.addMetadata(f.Name, string(v))
 	case "grpc-trace-bin":
 		v, err := decodeBinHeader(f.Value)
 		if err != nil {
-			return status.Errorf(codes.Internal, "transport: malformed grpc-trace-bin: %v", err)
+			d.data.grpcErr = status.Errorf(codes.Internal, "transport: malformed grpc-trace-bin: %v", err)
+			return
 		}
-		d.statsTrace = v
+		d.data.statsTrace = v
 		d.addMetadata(f.Name, string(v))
 	default:
 		if isReservedHeader(f.Name) && !isWhitelistedHeader(f.Name) {
@@ -359,11 +413,10 @@
 		v, err := decodeMetadataHeader(f.Name, f.Value)
 		if err != nil {
 			errorf("Failed to decode metadata header (%q, %q): %v", f.Name, f.Value, err)
-			return nil
+			return
 		}
 		d.addMetadata(f.Name, v)
 	}
-	return nil
 }
 
 type timeoutUnit uint8
diff --git a/vendor/google.golang.org/grpc/internal/transport/transport.go b/vendor/google.golang.org/grpc/internal/transport/transport.go
index 2580aa7..0f33c9c 100644
--- a/vendor/google.golang.org/grpc/internal/transport/transport.go
+++ b/vendor/google.golang.org/grpc/internal/transport/transport.go
@@ -22,6 +22,7 @@
 package transport
 
 import (
+	"bytes"
 	"context"
 	"errors"
 	"fmt"
@@ -39,10 +40,32 @@
 	"google.golang.org/grpc/tap"
 )
 
+type bufferPool struct {
+	pool sync.Pool
+}
+
+func newBufferPool() *bufferPool {
+	return &bufferPool{
+		pool: sync.Pool{
+			New: func() interface{} {
+				return new(bytes.Buffer)
+			},
+		},
+	}
+}
+
+func (p *bufferPool) get() *bytes.Buffer {
+	return p.pool.Get().(*bytes.Buffer)
+}
+
+func (p *bufferPool) put(b *bytes.Buffer) {
+	p.pool.Put(b)
+}
+
 // recvMsg represents the received msg from the transport. All transport
 // protocol specific info has been removed.
 type recvMsg struct {
-	data []byte
+	buffer *bytes.Buffer
 	// nil: received some data
 	// io.EOF: stream is completed. data is nil.
 	// other non-nil error: transport failure. data is nil.
@@ -117,8 +140,9 @@
 	ctx         context.Context
 	ctxDone     <-chan struct{} // cache of ctx.Done() (for performance).
 	recv        *recvBuffer
-	last        []byte // Stores the remaining data in the previous calls.
+	last        *bytes.Buffer // Stores the remaining data in the previous calls.
 	err         error
+	freeBuffer  func(*bytes.Buffer)
 }
 
 // Read reads the next len(p) bytes from last. If last is drained, it tries to
@@ -128,10 +152,13 @@
 	if r.err != nil {
 		return 0, r.err
 	}
-	if r.last != nil && len(r.last) > 0 {
+	if r.last != nil {
 		// Read remaining data left in last call.
-		copied := copy(p, r.last)
-		r.last = r.last[copied:]
+		copied, _ := r.last.Read(p)
+		if r.last.Len() == 0 {
+			r.freeBuffer(r.last)
+			r.last = nil
+		}
 		return copied, nil
 	}
 	if r.closeStream != nil {
@@ -170,8 +197,13 @@
 	if m.err != nil {
 		return 0, m.err
 	}
-	copied := copy(p, m.data)
-	r.last = m.data[copied:]
+	copied, _ := m.buffer.Read(p)
+	if m.buffer.Len() == 0 {
+		r.freeBuffer(m.buffer)
+		r.last = nil
+	} else {
+		r.last = m.buffer
+	}
 	return copied, nil
 }
 
@@ -204,8 +236,8 @@
 	// is used to adjust flow control, if needed.
 	requestRead func(int)
 
-	headerChan chan struct{} // closed to indicate the end of header metadata.
-	headerDone uint32        // set when headerChan is closed. Used to avoid closing headerChan multiple times.
+	headerChan       chan struct{} // closed to indicate the end of header metadata.
+	headerChanClosed uint32        // set when headerChan is closed. Used to avoid closing headerChan multiple times.
 
 	// hdrMu protects header and trailer metadata on the server-side.
 	hdrMu sync.Mutex
@@ -327,8 +359,7 @@
 	if err != nil {
 		return false, err
 	}
-	// if !headerDone, some other connection error occurred.
-	return s.noHeaders && atomic.LoadUint32(&s.headerDone) == 1, nil
+	return s.noHeaders, nil
 }
 
 // Trailer returns the cached trailer metedata. Note that if it is not called
@@ -579,9 +610,12 @@
 	// is called only once.
 	Close() error
 
-	// GracefulClose starts to tear down the transport. It stops accepting
-	// new RPCs and wait the completion of the pending RPCs.
-	GracefulClose() error
+	// GracefulClose starts to tear down the transport: the transport will stop
+	// accepting new RPCs and NewStream will return error. Once all streams are
+	// finished, the transport will close.
+	//
+	// It does not block.
+	GracefulClose()
 
 	// Write sends the data for the given stream. A nil stream indicates
 	// the write is to be performed on the transport as a whole.
@@ -611,6 +645,9 @@
 	// GetGoAwayReason returns the reason why GoAway frame was received.
 	GetGoAwayReason() GoAwayReason
 
+	// RemoteAddr returns the remote network address.
+	RemoteAddr() net.Addr
+
 	// IncrMsgSent increments the number of message sent through this transport.
 	IncrMsgSent()