[VOL-4289]  Proto changes for gRPC migration

Change-Id: I317a0a865ccf78d0c37aa229c50d293a3f66c8bb
diff --git a/vendor/google.golang.org/grpc/balancer/grpclb/state/state.go b/vendor/google.golang.org/grpc/balancer/grpclb/state/state.go
new file mode 100644
index 0000000..a24264a
--- /dev/null
+++ b/vendor/google.golang.org/grpc/balancer/grpclb/state/state.go
@@ -0,0 +1,51 @@
+/*
+ *
+ * Copyright 2020 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 state declares grpclb types to be set by resolvers wishing to pass
+// information to grpclb via resolver.State Attributes.
+package state
+
+import (
+	"google.golang.org/grpc/resolver"
+)
+
+// keyType is the key to use for storing State in Attributes.
+type keyType string
+
+const key = keyType("grpc.grpclb.state")
+
+// State contains gRPCLB-relevant data passed from the name resolver.
+type State struct {
+	// BalancerAddresses contains the remote load balancer address(es).  If
+	// set, overrides any resolver-provided addresses with Type of GRPCLB.
+	BalancerAddresses []resolver.Address
+}
+
+// Set returns a copy of the provided state with attributes containing s.  s's
+// data should not be mutated after calling Set.
+func Set(state resolver.State, s *State) resolver.State {
+	state.Attributes = state.Attributes.WithValues(key, s)
+	return state
+}
+
+// Get returns the grpclb State in the resolver.State, or nil if not present.
+// The returned data should not be mutated.
+func Get(state resolver.State) *State {
+	s, _ := state.Attributes.Value(key).(*State)
+	return s
+}