code: public Observable<EventSubscriptionInner> getAsync(String scope, String eventSubscriptionName) {
          return getWithServiceResponseAsync(scope, eventSubscriptionName).map(new Func1<ServiceResponse<EventSubscriptionInner>, EventSubscriptionInner>() {
              @Override
              public EventSubscriptionInner call(ServiceResponse<EventSubscriptionInner> response) {
                  return response.body();
              }
          });
      }
docs: Get an event subscription.
  Get properties of an event subscription.
  
  @param scope The scope of the event subscription. The scope can be a subscription, or a resource group, or a top level resource belonging to a resource provider namespace, or an EventGrid topic. For example, use '/subscriptions/{subscriptionId}/' for a subscription, '/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}' for a resource group, and '/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/{resourceProviderNamespace}/{resourceType}/{resourceName}' for a resource, and '/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.EventGrid/topics/{topicName}' for an EventGrid topic.
  @param eventSubscriptionName Name of the event subscription
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the EventSubscriptionInner object