[VOL-4290] Voltha go library updates for gRPC migration

Change-Id: I1aa2774beb6b7ed7419bc45aeb53fcae8a8ecda0
diff --git a/pkg/kafka/client.go b/pkg/kafka/client.go
index eee9631..fdc05bc 100755
--- a/pkg/kafka/client.go
+++ b/pkg/kafka/client.go
@@ -12,6 +12,11 @@
  * 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.
+ *
+ *
+ * NOTE:  The kafka client is used to publish events on Kafka in voltha
+ * release 2.9.  It is no longer used for inter voltha container
+ * communication.
  */
 package kafka
 
@@ -19,7 +24,7 @@
 	"context"
 	"time"
 
-	ca "github.com/opencord/voltha-protos/v4/go/inter_container"
+	"github.com/golang/protobuf/proto"
 )
 
 const (
@@ -55,6 +60,7 @@
 	DefaultNumberReplicas           = 1
 	DefaultAutoCreateTopic          = false
 	DefaultMetadataMaxRetry         = 3
+	DefaultMaxRetries               = 3
 	DefaultLivenessChannelInterval  = time.Second * 30
 )
 
@@ -64,8 +70,8 @@
 	Stop(ctx context.Context)
 	CreateTopic(ctx context.Context, topic *Topic, numPartition int, repFactor int) error
 	DeleteTopic(ctx context.Context, topic *Topic) error
-	Subscribe(ctx context.Context, topic *Topic, kvArgs ...*KVArg) (<-chan *ca.InterContainerMessage, error)
-	UnSubscribe(ctx context.Context, topic *Topic, ch <-chan *ca.InterContainerMessage) error
+	Subscribe(ctx context.Context, topic *Topic, kvArgs ...*KVArg) (<-chan proto.Message, error)
+	UnSubscribe(ctx context.Context, topic *Topic, ch <-chan proto.Message) error
 	SubscribeForMetadata(context.Context, func(fromTopic string, timestamp time.Time))
 	Send(ctx context.Context, msg interface{}, topic *Topic, keys ...string) error
 	SendLiveness(ctx context.Context) error