Merge pull request #37411 from tonistiigi/vendor-containerd

vendor: update containerd to b41633746

vendor.conf

@@ -114,14 +114,14 @@ github.com/googleapis/gax-go v2.0.0
 google.golang.org/genproto 694d95ba50e67b2e363f3483057db5d4910c18f9
 
 # containerd
-github.com/containerd/containerd 08f7ee9828af1783dc98cc5cc1739e915697c667
+github.com/containerd/containerd b41633746ed4833f52c3c071e8edcfa2713e5677
 github.com/containerd/fifo 3d5202aec260678c48179c56f40e6f38a095738c
 github.com/containerd/continuity d3c23511c1bf5851696cba83143d9cbcd666869b
 github.com/containerd/cgroups fe281dd265766145e943a034aa41086474ea6130
-github.com/containerd/console 9290d21dc56074581f619579c43d970b4514bc08
+github.com/containerd/console 5d1b48d6114b8c9666f0c8b916f871af97b0a761
 github.com/containerd/go-runc f271fa2021de855d4d918dbef83c5fe19db1bdd
-github.com/containerd/typeurl f6943554a7e7e88b3c14aad190bf05932da84788
-github.com/stevvooe/ttrpc d4528379866b0ce7e9d71f3eb96f0582fc374577
+github.com/containerd/typeurl a93fcdb778cd272c6e9b3028b2f42d813e785d40
+github.com/containerd/ttrpc 94dde388801693c54f88a6596f713b51a8b30b2d
 github.com/gogo/googleapis 08a7655d27152912db7aaf4f983275eaf8d128ef
 
 # cluster

vendor/github.com/containerd/console/console_linux.go

@@ -262,10 +262,14 @@ func (ec *EpollConsole) Shutdown(close func(int) error) error {
 
 // signalRead signals that the console is readable.
 func (ec *EpollConsole) signalRead() {
+	ec.readc.L.Lock()
 	ec.readc.Signal()
+	ec.readc.L.Unlock()
 }
 
 // signalWrite signals that the console is writable.
 func (ec *EpollConsole) signalWrite() {
+	ec.writec.L.Lock()
 	ec.writec.Signal()
+	ec.writec.L.Unlock()
 }

vendor/github.com/containerd/containerd/cio/io.go

@@ -255,3 +255,14 @@ func (l *logIO) Wait() {
 func (l *logIO) Close() error {
 	return nil
 }
+
+// Load the io for a container but do not attach
+//
+// Allows io to be loaded on the task for deletion without
+// starting copy routines
+func Load(set *FIFOSet) (IO, error) {
+	return &cio{
+		config:  set.Config,
+		closers: []io.Closer{set},
+	}, nil
+}

vendor/github.com/containerd/containerd/container.go

@@ -307,6 +307,12 @@ func (c *container) get(ctx context.Context) (containers.Container, error) {
 
 // get the existing fifo paths from the task information stored by the daemon
 func attachExistingIO(response *tasks.GetResponse, ioAttach cio.Attach) (cio.IO, error) {
+	fifoSet := loadFifos(response)
+	return ioAttach(fifoSet)
+}
+
+// loadFifos loads the containers fifos
+func loadFifos(response *tasks.GetResponse) *cio.FIFOSet {
 	path := getFifoDir([]string{
 		response.Process.Stdin,
 		response.Process.Stdout,
@@ -315,13 +321,12 @@ func attachExistingIO(response *tasks.GetResponse, ioAttach cio.Attach) (cio.IO,
 	closer := func() error {
 		return os.RemoveAll(path)
 	}
-	fifoSet := cio.NewFIFOSet(cio.Config{
+	return cio.NewFIFOSet(cio.Config{
 		Stdin:    response.Process.Stdin,
 		Stdout:   response.Process.Stdout,
 		Stderr:   response.Process.Stderr,
 		Terminal: response.Process.Terminal,
 	}, closer)
-	return ioAttach(fifoSet)
 }
 
 // getFifoDir looks for any non-empty path for a stdio fifo

vendor/github.com/containerd/containerd/oci/spec_unix.go

@@ -153,7 +153,9 @@ func createDefaultSpec(ctx context.Context, id string) (*Spec, error) {
 		},
 		Linux: &specs.Linux{
 			MaskedPaths: []string{
+				"/proc/acpi",
 				"/proc/kcore",
+				"/proc/keys",
 				"/proc/latency_stats",
 				"/proc/timer_list",
 				"/proc/timer_stats",

vendor/github.com/containerd/containerd/runtime/linux/process.go

@@ -26,8 +26,8 @@ import (
 	"github.com/containerd/containerd/errdefs"
 	"github.com/containerd/containerd/runtime"
 	shim "github.com/containerd/containerd/runtime/shim/v1"
+	"github.com/containerd/ttrpc"
 	"github.com/pkg/errors"
-	"github.com/stevvooe/ttrpc"
 )
 
 // Process implements a linux process

vendor/github.com/containerd/containerd/runtime/linux/task.go

@@ -32,9 +32,9 @@ import (
 	"github.com/containerd/containerd/runtime/shim/client"
 	shim "github.com/containerd/containerd/runtime/shim/v1"
 	runc "github.com/containerd/go-runc"
+	"github.com/containerd/ttrpc"
 	"github.com/gogo/protobuf/types"
 	"github.com/pkg/errors"
-	"github.com/stevvooe/ttrpc"
 )
 
 // Task on a linux based system

vendor/github.com/containerd/containerd/runtime/shim/client/client.go

@@ -31,9 +31,9 @@ import (
 
 	"golang.org/x/sys/unix"
 
+	"github.com/containerd/ttrpc"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
-	"github.com/stevvooe/ttrpc"
 
 	"github.com/containerd/containerd/events"
 	"github.com/containerd/containerd/log"

vendor/github.com/containerd/containerd/runtime/shim/v1/shim.pb.go

@@ -50,7 +50,7 @@ import strings "strings"
 import reflect "reflect"
 
 import context "context"
-import ttrpc "github.com/stevvooe/ttrpc"
+import ttrpc "github.com/containerd/ttrpc"
 
 import io "io"
 

vendor/github.com/containerd/containerd/vendor.conf

@@ -1,7 +1,7 @@
 github.com/containerd/go-runc f271fa2021de855d4d918dbef83c5fe19db1bdd5
-github.com/containerd/console 9290d21dc56074581f619579c43d970b4514bc08
+github.com/containerd/console 5d1b48d6114b8c9666f0c8b916f871af97b0a761
 github.com/containerd/cgroups fe281dd265766145e943a034aa41086474ea6130
-github.com/containerd/typeurl f6943554a7e7e88b3c14aad190bf05932da84788
+github.com/containerd/typeurl a93fcdb778cd272c6e9b3028b2f42d813e785d40
 github.com/containerd/fifo 3d5202aec260678c48179c56f40e6f38a095738c
 github.com/containerd/btrfs 2e1aa0ddf94f91fa282b6ed87c23bf0d64911244
 github.com/containerd/continuity d3c23511c1bf5851696cba83143d9cbcd666869b
@@ -37,13 +37,14 @@ github.com/Microsoft/hcsshim v0.6.11
 github.com/boltdb/bolt e9cf4fae01b5a8ff89d0ec6b32f0d9c9f79aefdd
 google.golang.org/genproto d80a6e20e776b0b17a324d0ba1ab50a39c8e8944
 golang.org/x/text 19e51611da83d6be54ddafce4a4af510cb3e9ea4
-github.com/stevvooe/ttrpc d4528379866b0ce7e9d71f3eb96f0582fc374577
+github.com/containerd/ttrpc 94dde388801693c54f88a6596f713b51a8b30b2d
 github.com/syndtr/gocapability db04d3cc01c8b54962a58ec7e491717d06cfcc16
 gotest.tools v2.1.0
 github.com/google/go-cmp v0.1.0
 
-github.com/containerd/cri 8bcb9a95394e8d7845da1d6a994d3ac2a86d22f0
-github.com/containerd/go-cni f2d7272f12d045b16ed924f50e91f9f9cecc55a7
+# cri dependencies
+github.com/containerd/cri v1.11.0
+github.com/containerd/go-cni 5882530828ecf62032409b298a3e8b19e08b6534
 github.com/blang/semver v3.1.0
 github.com/containernetworking/cni v0.6.0
 github.com/containernetworking/plugins v0.7.0
@@ -57,22 +58,26 @@ github.com/golang/glog 44145f04b68cf362d9c4df2182967c2275eaefed
 github.com/google/gofuzz 44d81051d367757e1c7c6a5a86423ece9afcf63c
 github.com/hashicorp/errwrap 7554cd9344cec97297fa6649b055a8c98c2a1e55
 github.com/hashicorp/go-multierror ed905158d87462226a13fe39ddf685ea65f1c11f
-github.com/json-iterator/go 1.0.4
-github.com/opencontainers/runtime-tools 6073aff4ac61897f75895123f7e24135204a404d
+github.com/json-iterator/go f2b4162afba35581b6d4a50d3b8f34e33c144682
+github.com/modern-go/reflect2 05fbef0ca5da472bbf96c9322b84a53edc03c9fd
+github.com/modern-go/concurrent 1.0.3
+github.com/opencontainers/runtime-tools v0.6.0
 github.com/opencontainers/selinux 4a2974bf1ee960774ffd517717f1f45325af0206
 github.com/seccomp/libseccomp-golang 32f571b70023028bd57d9288c20efbcb237f3ce0
-github.com/spf13/pflag v1.0.0
 github.com/tchap/go-patricia 5ad6cdb7538b0097d5598c7e57f0a24072adf7dc
+github.com/xeipuuv/gojsonpointer 4e3ac2762d5f479393488629ee9370b50873b3a6
+github.com/xeipuuv/gojsonreference bd5ef7bd5415a7ac448318e64f11a24cd21e594b
+github.com/xeipuuv/gojsonschema 1d523034197ff1f222f6429836dd36a2457a1874
 golang.org/x/crypto 49796115aa4b964c318aad4f3084fdb41e9aa067
 golang.org/x/time f51c12702a4d776e4c1fa9b0fabab841babae631
 gopkg.in/inf.v0 3887ee99ecf07df5b447e9b00d9c0b2adaa9f3e4
 gopkg.in/yaml.v2 53feefa2559fb8dfa8d81baad31be332c97d6c77
-k8s.io/api 7e796de92438aede7cb5d6bcf6c10f4fa65db560
-k8s.io/apimachinery fcb9a12f7875d01f8390b28faedc37dcf2e713b9
-k8s.io/apiserver 4a8377c547bbff4576a35b5b5bf4026d9b5aa763
-k8s.io/client-go b9a0cf870f239c4a4ecfd3feb075a50e7cbe1473
-k8s.io/kubernetes v1.10.0
-k8s.io/utils 258e2a2fa64568210fbd6267cf1d8fd87c3cb86e
+k8s.io/api 9e5ffd1f1320950b238cfce291b926411f0af722
+k8s.io/apimachinery ed135c5b96450fd24e5e981c708114fbbd950697
+k8s.io/apiserver a90e3a95c2e91b944bfca8225c4e0d12e42a9eb5
+k8s.io/client-go 03bfb9bdcfe5482795b999f39ca3ed9ad42ce5bb
+k8s.io/kubernetes v1.11.0
+k8s.io/utils 733eca437aa39379e4bcc25e726439dfca40fcff
 
 # zfs dependencies
 github.com/containerd/zfs 9a0b8b8b5982014b729cd34eb7cd7a11062aa6ec

vendor/github.com/containerd/ttrpc/README.md

@@ -1,6 +1,6 @@
 # ttrpc
 
-[![Build Status](https://travis-ci.org/stevvooe/ttrpc.svg?branch=master)](https://travis-ci.org/stevvooe/ttrpc)
+[![Build Status](https://travis-ci.org/containerd/ttrpc.svg?branch=master)](https://travis-ci.org/containerd/ttrpc)
 
 GRPC for low-memory environments.
 
@@ -25,7 +25,7 @@ Create a gogo vanity binary (see
 [`cmd/protoc-gen-gogottrpc/main.go`](cmd/protoc-gen-gogottrpc/main.go) for an
 example with the ttrpc plugin enabled.
 
-It's recommended to use [`protobuild`](https://github.com/stevvooe/protobuild)
+It's recommended to use [`protobuild`](https://github.com//stevvooe/protobuild)
 to build the protobufs for this project, but this will work with protoc
 directly, if required.
 

vendor/github.com/containerd/ttrpc/channel.go

@@ -1,3 +1,19 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
 package ttrpc
 
 import (

vendor/github.com/containerd/ttrpc/client.go

@@ -1,3 +1,19 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
 package ttrpc
 
 import (
@@ -9,9 +25,9 @@ import (
 	"sync"
 	"syscall"
 
-	"github.com/containerd/containerd/log"
 	"github.com/gogo/protobuf/proto"
 	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
 	"google.golang.org/grpc/status"
 )
 
@@ -180,7 +196,7 @@ func (c *Client) run() {
 		case msg := <-incoming:
 			call, ok := waiters[msg.StreamID]
 			if !ok {
-				log.L.Errorf("ttrpc: received message for unknown channel %v", msg.StreamID)
+				logrus.Errorf("ttrpc: received message for unknown channel %v", msg.StreamID)
 				continue
 			}
 

vendor/github.com/containerd/ttrpc/codec.go

@@ -0,0 +1,42 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package ttrpc
+
+import (
+	"github.com/gogo/protobuf/proto"
+	"github.com/pkg/errors"
+)
+
+type codec struct{}
+
+func (c codec) Marshal(msg interface{}) ([]byte, error) {
+	switch v := msg.(type) {
+	case proto.Message:
+		return proto.Marshal(v)
+	default:
+		return nil, errors.Errorf("ttrpc: cannot marshal unknown type: %T", msg)
+	}
+}
+
+func (c codec) Unmarshal(p []byte, msg interface{}) error {
+	switch v := msg.(type) {
+	case proto.Message:
+		return proto.Unmarshal(p, v)
+	default:
+		return errors.Errorf("ttrpc: cannot unmarshal into unknown type: %T", msg)
+	}
+}

vendor/github.com/containerd/ttrpc/config.go

@@ -0,0 +1,39 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package ttrpc
+
+import "github.com/pkg/errors"
+
+type serverConfig struct {
+	handshaker Handshaker
+}
+
+type ServerOpt func(*serverConfig) error
+
+// WithServerHandshaker can be passed to NewServer to ensure that the
+// handshaker is called before every connection attempt.
+//
+// Only one handshaker is allowed per server.
+func WithServerHandshaker(handshaker Handshaker) ServerOpt {
+	return func(c *serverConfig) error {
+		if c.handshaker != nil {
+			return errors.New("only one handshaker allowed per server")
+		}
+		c.handshaker = handshaker
+		return nil
+	}
+}

vendor/github.com/containerd/ttrpc/handshake.go

@@ -1,3 +1,19 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
 package ttrpc
 
 import (

vendor/github.com/containerd/ttrpc/server.go

@@ -1,3 +1,19 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
 package ttrpc
 
 import (
@@ -9,8 +25,8 @@ import (
 	"sync/atomic"
 	"time"
 
-	"github.com/containerd/containerd/log"
 	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/status"
 )
@@ -51,12 +67,11 @@ func (s *Server) Register(name string, methods map[string]Method) {
 	s.services.register(name, methods)
 }
 
-func (s *Server) Serve(l net.Listener) error {
+func (s *Server) Serve(ctx context.Context, l net.Listener) error {
 	s.addListener(l)
 	defer s.closeListener(l)
 
 	var (
-		ctx        = context.Background()
 		backoff    time.Duration
 		handshaker = s.config.handshaker
 	)
@@ -88,7 +103,7 @@ func (s *Server) Serve(l net.Listener) error {
 				}
 
 				sleep := time.Duration(rand.Int63n(int64(backoff)))
-				log.L.WithError(err).Errorf("ttrpc: failed accept; backoff %v", sleep)
+				logrus.WithError(err).Errorf("ttrpc: failed accept; backoff %v", sleep)
 				time.Sleep(sleep)
 				continue
 			}
@@ -100,7 +115,7 @@ func (s *Server) Serve(l net.Listener) error {
 
 		approved, handshake, err := handshaker.Handshake(ctx, conn)
 		if err != nil {
-			log.L.WithError(err).Errorf("ttrpc: refusing connection after handshake")
+			logrus.WithError(err).Errorf("ttrpc: refusing connection after handshake")
 			conn.Close()
 			continue
 		}
@@ -416,12 +431,12 @@ func (c *serverConn) run(sctx context.Context) {
 		case response := <-responses:
 			p, err := c.server.codec.Marshal(response.resp)
 			if err != nil {
-				log.L.WithError(err).Error("failed marshaling response")
+				logrus.WithError(err).Error("failed marshaling response")
 				return
 			}
 
 			if err := ch.send(ctx, response.id, messageTypeResponse, p); err != nil {
-				log.L.WithError(err).Error("failed sending message on channel")
+				logrus.WithError(err).Error("failed sending message on channel")
 				return
 			}
 
@@ -432,7 +447,7 @@ func (c *serverConn) run(sctx context.Context) {
 			// requests due to a terminal error.
 			recvErr = nil // connection is now "closing"
 			if err != nil && err != io.EOF {
-				log.L.WithError(err).Error("error receiving message")
+				logrus.WithError(err).Error("error receiving message")
 			}
 		case <-shutdown:
 			return

vendor/github.com/containerd/ttrpc/services.go

@@ -1,3 +1,19 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
 package ttrpc
 
 import (

vendor/github.com/containerd/ttrpc/types.go

@@ -1,3 +1,19 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
 package ttrpc
 
 import (

vendor/github.com/containerd/ttrpc/unixcreds_linux.go

@@ -1,3 +1,19 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
 package ttrpc
 
 import (

vendor/github.com/containerd/typeurl/types.go

@@ -1,3 +1,19 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
 package typeurl
 
 import (

vendor/github.com/stevvooe/ttrpc/codec.go

@@ -1,26 +0,0 @@
-package ttrpc
-
-import (
-	"github.com/gogo/protobuf/proto"
-	"github.com/pkg/errors"
-)
-
-type codec struct{}
-
-func (c codec) Marshal(msg interface{}) ([]byte, error) {
-	switch v := msg.(type) {
-	case proto.Message:
-		return proto.Marshal(v)
-	default:
-		return nil, errors.Errorf("ttrpc: cannot marshal unknown type: %T", msg)
-	}
-}
-
-func (c codec) Unmarshal(p []byte, msg interface{}) error {
-	switch v := msg.(type) {
-	case proto.Message:
-		return proto.Unmarshal(p, v)
-	default:
-		return errors.Errorf("ttrpc: cannot unmarshal into unknown type: %T", msg)
-	}
-}

vendor/github.com/stevvooe/ttrpc/config.go

@@ -1,23 +0,0 @@
-package ttrpc
-
-import "github.com/pkg/errors"
-
-type serverConfig struct {
-	handshaker Handshaker
-}
-
-type ServerOpt func(*serverConfig) error
-
-// WithServerHandshaker can be passed to NewServer to ensure that the
-// handshaker is called before every connection attempt.
-//
-// Only one handshaker is allowed per server.
-func WithServerHandshaker(handshaker Handshaker) ServerOpt {
-	return func(c *serverConfig) error {
-		if c.handshaker != nil {
-			return errors.New("only one handshaker allowed per server")
-		}
-		c.handshaker = handshaker
-		return nil
-	}
-}