Shutdown before re-opening

@@ -79,6 +79,7 @@ public class EdgeGrpcClient implements EdgeRpcClient {
                 throw new RuntimeException(e);
             }
         }
+        gracefulShutdown();
         channel = builder.build();
         EdgeRpcServiceGrpc.EdgeRpcServiceStub stub = EdgeRpcServiceGrpc.newStub(channel);
         log.info("[{}] Sending a connect request to the TB!", edgeKey);
@@ -89,6 +90,16 @@ public class EdgeGrpcClient implements EdgeRpcClient {
                 .build());
     }
 
+    private void gracefulShutdown() {
+        try {
+            if (channel != null) {
+                channel.shutdown().awaitTermination(timeoutSecs, TimeUnit.SECONDS);
+            }
+        } catch (InterruptedException e) {
+            log.debug("Error during shutdown of the previous channel", e);
+        }
+    }
+
     @Override
     public void disconnect() throws InterruptedException {
         inputStream.onCompleted();