code: public Observable<Void> deleteAuthorizationRuleAsync(String resourceGroupName, String namespaceName, String notificationHubName, String authorizationRuleName) {
          return deleteAuthorizationRuleWithServiceResponseAsync(resourceGroupName, namespaceName, notificationHubName, authorizationRuleName).map(new Func1<ServiceResponse<Void>, Void>() {
              @Override
              public Void call(ServiceResponse<Void> response) {
                  return response.body();
              }
          });
      }
docs: Deletes a notificationHub authorization rule.
  
  @param resourceGroupName The name of the resource group.
  @param namespaceName The namespace name.
  @param notificationHubName The notification hub name.
  @param authorizationRuleName Authorization Rule Name.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the {@link ServiceResponse} object if successful.