[VOL-4291] OfAgent changes for gRPC migration

Change-Id: I8da1db6df49d478ef24ec8f9bd719e9692f48a7f
diff --git a/vendor/go.uber.org/atomic/error_ext.go b/vendor/go.uber.org/atomic/error_ext.go
new file mode 100644
index 0000000..ffe0be2
--- /dev/null
+++ b/vendor/go.uber.org/atomic/error_ext.go
@@ -0,0 +1,39 @@
+// Copyright (c) 2020 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package atomic
+
+// atomic.Value panics on nil inputs, or if the underlying type changes.
+// Stabilize by always storing a custom struct that we control.
+
+//go:generate bin/gen-atomicwrapper -name=Error -type=error -wrapped=Value -pack=packError -unpack=unpackError -file=error.go
+
+type packedError struct{ Value error }
+
+func packError(v error) interface{} {
+	return packedError{v}
+}
+
+func unpackError(v interface{}) error {
+	if err, ok := v.(packedError); ok {
+		return err.Value
+	}
+	return nil
+}