[VOL-4291] OfAgent changes for gRPC migration

Change-Id: I8da1db6df49d478ef24ec8f9bd719e9692f48a7f
diff --git a/vendor/google.golang.org/protobuf/internal/impl/codec_map_go112.go b/vendor/google.golang.org/protobuf/internal/impl/codec_map_go112.go
new file mode 100644
index 0000000..1533ef6
--- /dev/null
+++ b/vendor/google.golang.org/protobuf/internal/impl/codec_map_go112.go
@@ -0,0 +1,11 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build go1.12
+
+package impl
+
+import "reflect"
+
+func mapRange(v reflect.Value) *reflect.MapIter { return v.MapRange() }