code: public Observable<Void> regenerateAccessKeyAsync(String resourceGroupName, String workflowName, KeyType keyType) {
          return regenerateAccessKeyWithServiceResponseAsync(resourceGroupName, workflowName, keyType).map(new Func1<ServiceResponse<Void>, Void>() {
              @Override
              public Void call(ServiceResponse<Void> response) {
                  return response.body();
              }
          });
      }
docs: Regenerates the callback URL access key for request triggers.
  
  @param resourceGroupName The resource group name.
  @param workflowName The workflow name.
  @param keyType The key type. Possible values include: 'NotSpecified', 'Primary', 'Secondary'
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the {@link ServiceResponse} object if successful.