code: public Observable<ServiceResponse<SignalRKeysInner>> regenerateKeyWithServiceResponseAsync(String resourceGroupName, String resourceName) {
          if (this.client.subscriptionId() == null) {
              throw new IllegalArgumentException("Parameter this.client.subscriptionId() is required and cannot be null.");
          }
          if (resourceGroupName == null) {
              throw new IllegalArgumentException("Parameter resourceGroupName is required and cannot be null.");
          }
          if (resourceName == null) {
              throw new IllegalArgumentException("Parameter resourceName is required and cannot be null.");
          }
          final KeyType keyType = null;
          RegenerateKeyParameters parameters = new RegenerateKeyParameters();
          parameters.withKeyType(null);
          Observable<Response<ResponseBody>> observable = service.regenerateKey(this.client.subscriptionId(), resourceGroupName, resourceName, this.client.apiVersion(), this.client.acceptLanguage(), parameters, this.client.userAgent());
          return client.getAzureClient().getPostOrDeleteResultAsync(observable, new TypeToken<SignalRKeysInner>() { }.getType());
      }
docs: Regenerate SignalR service access key. PrimaryKey and SecondaryKey cannot be regenerated at the same time.
  
  @param resourceGroupName The name of the resource group that contains the resource. You can obtain this value from the Azure Resource Manager API or the portal.
  @param resourceName The name of the SignalR resource.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable for the request