code: public ServiceFuture<Void> startAsync(String resourceGroupName, String applicationGatewayName, final ServiceCallback<Void> serviceCallback) {
          return ServiceFuture.fromResponse(startWithServiceResponseAsync(resourceGroupName, applicationGatewayName), serviceCallback);
      }
docs: Starts the specified application gateway.
  
  @param resourceGroupName The name of the resource group.
  @param applicationGatewayName The name of the application gateway.
  @param serviceCallback the async ServiceCallback to handle successful and failed responses.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the {@link ServiceFuture} object