code: public Observable<List<AnnotationInner>> getAsync(String resourceGroupName, String resourceName, String annotationId) {
          return getWithServiceResponseAsync(resourceGroupName, resourceName, annotationId).map(new Func1<ServiceResponse<List<AnnotationInner>>, List<AnnotationInner>>() {
              @Override
              public List<AnnotationInner> call(ServiceResponse<List<AnnotationInner>> response) {
                  return response.body();
              }
          });
      }
docs: Get the annotation for given id.
  
  @param resourceGroupName The name of the resource group.
  @param resourceName The name of the Application Insights component resource.
  @param annotationId The unique annotation ID. This is unique within a Application Insights component.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the List&lt;AnnotationInner&gt; object