code: public Observable<List<PerformanceTierPropertiesInner>> listAsync(String locationName) {
          return listWithServiceResponseAsync(locationName).map(new Func1<ServiceResponse<List<PerformanceTierPropertiesInner>>, List<PerformanceTierPropertiesInner>>() {
              @Override
              public List<PerformanceTierPropertiesInner> call(ServiceResponse<List<PerformanceTierPropertiesInner>> response) {
                  return response.body();
              }
          });
      }
docs: List all the performance tiers at specified location in a given subscription.
  
  @param locationName The name of the location.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the List&lt;PerformanceTierPropertiesInner&gt; object