Update go.mod and vendor

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

@@ -1,107 +0,0 @@
-/*
-   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 (
-	"context"
-	"strings"
-)
-
-// MD is the user type for ttrpc metadata
-type MD map[string][]string
-
-// Get returns the metadata for a given key when they exist.
-// If there is no metadata, a nil slice and false are returned.
-func (m MD) Get(key string) ([]string, bool) {
-	key = strings.ToLower(key)
-	list, ok := m[key]
-	if !ok || len(list) == 0 {
-		return nil, false
-	}
-
-	return list, true
-}
-
-// Set sets the provided values for a given key.
-// The values will overwrite any existing values.
-// If no values provided, a key will be deleted.
-func (m MD) Set(key string, values ...string) {
-	key = strings.ToLower(key)
-	if len(values) == 0 {
-		delete(m, key)
-		return
-	}
-	m[key] = values
-}
-
-// Append appends additional values to the given key.
-func (m MD) Append(key string, values ...string) {
-	key = strings.ToLower(key)
-	if len(values) == 0 {
-		return
-	}
-	current, ok := m[key]
-	if ok {
-		m.Set(key, append(current, values...)...)
-	} else {
-		m.Set(key, values...)
-	}
-}
-
-func (m MD) setRequest(r *Request) {
-	for k, values := range m {
-		for _, v := range values {
-			r.Metadata = append(r.Metadata, &KeyValue{
-				Key:   k,
-				Value: v,
-			})
-		}
-	}
-}
-
-func (m MD) fromRequest(r *Request) {
-	for _, kv := range r.Metadata {
-		m[kv.Key] = append(m[kv.Key], kv.Value)
-	}
-}
-
-type metadataKey struct{}
-
-// GetMetadata retrieves metadata from context.Context (previously attached with WithMetadata)
-func GetMetadata(ctx context.Context) (MD, bool) {
-	metadata, ok := ctx.Value(metadataKey{}).(MD)
-	return metadata, ok
-}
-
-// GetMetadataValue gets a specific metadata value by name from context.Context
-func GetMetadataValue(ctx context.Context, name string) (string, bool) {
-	metadata, ok := GetMetadata(ctx)
-	if !ok {
-		return "", false
-	}
-
-	if list, ok := metadata.Get(name); ok {
-		return list[0], true
-	}
-
-	return "", false
-}
-
-// WithMetadata attaches metadata map to a context.Context
-func WithMetadata(ctx context.Context, md MD) context.Context {
-	return context.WithValue(ctx, metadataKey{}, md)
-}