VOL-1334 : Fixed concurrency issues

- Semaphores were added at the different layers of the model
- Made the proxy interfaces more robust
- Eliminated problems while retrieving latest data in concurrent mode

Change-Id: I7854105d7effa10e5cb704f5d9917569ab184f84
diff --git a/db/model/event_bus_client.go b/db/model/event_bus_client.go
index 227cb3c..f038cad 100644
--- a/db/model/event_bus_client.go
+++ b/db/model/event_bus_client.go
@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package model
 
 import (
@@ -20,13 +21,16 @@
 	"github.com/opencord/voltha-go/protos/voltha"
 )
 
+// EventBusClient is an abstraction layer structure to communicate with an event bus mechanism
 type EventBusClient struct {
 }
 
+// NewEventBusClient creates a new EventBusClient instance
 func NewEventBusClient() *EventBusClient {
 	return &EventBusClient{}
 }
 
+// Publish sends a event to the bus
 func (ebc *EventBusClient) Publish(topic string, event voltha.ConfigEvent) {
 	log.Debugf("publishing event:%+v, topic:%s\n", event, topic)
 }