diff --git a/go/vendor/google.golang.org/grpc/credentials/go19.go b/go/vendor/google.golang.org/grpc/credentials/go19.go
new file mode 100644
index 0000000..2a4ca1a
--- /dev/null
+++ b/go/vendor/google.golang.org/grpc/credentials/go19.go
@@ -0,0 +1,35 @@
+// +build go1.9,!appengine
+
+/*
+ *
+ * Copyright 2018 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 (
+	"errors"
+	"syscall"
+)
+
+// implements the syscall.Conn interface
+func (c tlsConn) SyscallConn() (syscall.RawConn, error) {
+	conn, ok := c.rawConn.(syscall.Conn)
+	if !ok {
+		return nil, errors.New("RawConn does not implement syscall.Conn")
+	}
+	return conn.SyscallConn()
+}