code: public Observable<ServiceKeysInner> listKeysAsync(String resourceGroupName, String mediaServiceName) {
          return listKeysWithServiceResponseAsync(resourceGroupName, mediaServiceName).map(new Func1<ServiceResponse<ServiceKeysInner>, ServiceKeysInner>() {
              @Override
              public ServiceKeysInner call(ServiceResponse<ServiceKeysInner> response) {
                  return response.body();
              }
          });
      }
docs: Lists the keys for a Media Service.
  
  @param resourceGroupName Name of the resource group within the Azure subscription.
  @param mediaServiceName Name of the Media Service.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the ServiceKeysInner object