Added support for Haystack tracing

vendor/google.golang.org/grpc/credentials/credentials_util_go18.go

@@ -1,38 +0,0 @@
-// +build go1.8
-
-/*
- *
- * Copyright 2017 gRPC 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 credentials
-
-import (
-	"crypto/tls"
-)
-
-// cloneTLSConfig returns a shallow clone of the exported
-// fields of cfg, ignoring the unexported sync.Once, which
-// contains a mutex and must not be copied.
-//
-// If cfg is nil, a new zero tls.Config is returned.
-func cloneTLSConfig(cfg *tls.Config) *tls.Config {
-	if cfg == nil {
-		return &tls.Config{}
-	}
-
-	return cfg.Clone()
-}